UC-NRLF 


GIFT   OF 


LABORATORY  LESSONS 


IN 


PHYSICAL  GEOGRAPHY 


BY 
LU  LESTER  EVERLY,   M.A. 

DEPARTMENT  OF  GEOGRAPHY,    STATE  NORMAL  SCHOOL,   WINONA,    MINN. 

RALPH   E.   BLOUNT,   A.  B. 
CALVIN   L.   WALTON,   Ph.D. 

TEACHERS   OF   PHYSICAL    GEOGRAPHY  IN  THE  CHICAGO 
HIGH    SCHOOLS 


NEW  YORK     •:•     CINCINNATI     •:•     CHICAGO 

AMERICAN   BOOK   COMPANY 


LABORATORY    LESSONS 


IN 


PHYSICAL    GEOGRAPHY 


BY 
LU    LESTER    EVERLY,    M.A. 

DEPARTMENT    OF    GEOGRAPHY,    STATE    NORMAL    SCHOOL,    WINONA,    MINN. 

RALPH   E.    BLOUNT,    A.B. 
CALVIN  L.  WALTON,  PH.D. 

TEACHERS   OF    PHYSICAL   GEOGRAPHY   IN   THE   CHICAGO 
HIGH    SCHOOLS 


NEW  YOEK  •:•  CINCINNATI  •:•  CHICAGO 

AMERICAN   BOOK   COMPANY 


COPYRIGHT,  1907,  BY 
LU  LESTER  EVERLY,  RALPH  E.   BLOUNT, 

AND 

CALVIN   L.   WAL1 


ENTERKD  AT  STATIONERS'  HALL,  LONDON. 

LABORATORY    t.F«SONS    IN    PIIY8.    UKOO. 
\V.   P.  I 


CONTENTS 

Exercises  marked  with  a  *  may  be  chosen  by  schools  that  cannot  give  a  full  year  to  the  subject. 

PAGE 

PREFACE      ...................  5 

LIST  OF  APPARATUS    .................  6 

MATHEMATICAL   GEOGRAPHY 

*1.   A  GLOBE  EXERCISE    .................  10 

*2.    THE  GLOBULAR  PROJECTION  OF  THE  WESTERN  HEMISPHERE  ........  12 

*3.    MERCATOR'S  MAP  OF  THE  EARTH       .............  15 

*4.    LENGTH  OF  DAY  AND  NIGHT      ..............  19 

*5.  SUNRISE  AND  SUNSET  GRAPHS  ..............  22 

6.    THE  PATH  OF  THE  SUN      ...............  23 

*7.  STANDARD  TIME  .......  ......  .....  26 

8.   THE  PHASES  OF  THE  MOON        ..............  28 

MATERIALS   OF  THE   EARTH'S   CRUST 

*9.    PRELIMINARY  STUDY  OF  MINERALS    .............  30 

*10.    THE  STUDY  OF  MINERALS  ...............  30 

*11.    THE  STUDY  OF  ROCKS         ...............  31 

12.  COMPOSITION  OF  SOIL           ...........         ....  34 

13.  IRON  COMPOUNDS         ................  36 

*14.    COAL   ...................  38 

*15.    HARD  AND  SOFT  WATER    ...............  39 

16.  f  STALACTITES  AND  STALAGMITES          .............  41 

17.  ALKALI  PLAINS  .................  43 

DRAINAGE   AND  LAND  FORMS 


18.    MODELING  ............ 

*19.    FIRST  EXERCISE  WITH  CONTOURS       ....... 

*20.    SECOND  EXERCISE  WITH  CONTOURS    ....... 

*21.    ILLINOIS.     LA  SALLE  SHEET.     DEVELOPMENT  OF  VALE'EYS      .. 
*22.    DRAINAGE  AREAS  OF  THE  UNITED  STATES        ..... 

23.  THE  MISSISSIPPI  RIVER       ......... 

24.  MINNESOTA.     ST.  PAUL  SHEET.     MISSISSIPPI  RIVER         ... 
*25.    IOWA-ILLINOIS.     SAVANNA  SHEET.     MISSISSIPPI  RIVER     ... 
*26.    LOUISIANA.     DONALDSONVILLE  SHEET.     MISSISSIPPI  RIVER      .. 

27.  MISSISSIPPI  RIVER  SHEET  No.  14      ....... 

28.  CALIFORNIA.     CUCAMONGA  SHEET.     ALLUVIAL  CONES      ... 
*29.    ILLINOIS.     OTTAWA  SHEET.     YOUNG  PLAIN       ..... 

30.  PICTURE  SUPPLEMENT  —  OTTAWA        ....... 

31.  NORTH  DAKOTA-MINNESOTA.     FARGO  SHEET.     YOUNG  LAKE  PLAIN 

32.  MARYLAND-VIRGINIA.     WICOMICO  SHEET.     DISSECTED  PLAIN  . 
*33.    WEST  VIRGINIA.     CHARLESTON  SHEET.     MATURE  DRAINAGE   .. 

34.    PICTURE  SUPPLEMENT  —  CHARLESTON 
*35.    KANSAS.     CALDWELL  SHEET.     OLD  DRAINAGE  .... 

36.    COLORADO.     LAMAR  SHEET.     IRRIGATED  PLAIN        .... 
*37.   ARIZONA.     KAIBAB  SHEET.     PLATEAUS 
*38.    PENNSYLVANIA.     HARRISBURG  SHEET.     APPALACHIAN  MOUNTAINS  . 

39.    COLORADO.     ANTHRACITE  SHEET.     ROCKY  MOUNTAINS 
*40.    CALIFORNIA.     SHASTA  SPECIAL  SHEET.     VOLCANIC  CONE         . 

41.   BOWLDER  CLAY,  OR  TILL  ... 


3025073 


PAGB 

*42.    COMPARATIVE  STUDY  OF  GLACIAL  AND  LAKE  (RIVER)  PEBBLES 

*43.    CALIFORNIA.     SHASTA  SPECIAL  SHEET.     ALPINE  GLACIERS 95 

*44.    WISCONSIN.     WHITEWATER  SHEET.     MORAINES  AND  DRUMLINS 97 

45.  PICTURE  SUPPLEMENT  —  WHITEWATER       ............  99 

46.  NEW  YORK.     WATKINS  SHEET.     A  GLACIAL  LAKE 101 

47.  NEW  YORK.     NIAGARA  SHEET,  OR  NIAGARA  FALLS  AND  VICINITY.     GLACIAL  EFFECTS         .         .  103 

48.  THE  CHICAGO  DISTRICT 105 

THE   ATMOSPHERE 

49.  EXPERIMENTS  WITH  CITY  GAS    .... 

50.  EXPERIMENTS  WITH  OXYGEN      ..............  109 

51.  EXPERIMENTS  WITH  NITROGEN  ..............  Ill 

52.  EXPERIMENTS  WITH  CARBON  DIOXIDE        .         .         .         .         .         .         .         .         .         .         .         .113 

*53.    LIGHT.     THE  COLORS  IN  SUNLIGHT 115 

*54.    LIGHT.     ABSORPTION  OF  COLORS 115 

*55.    ATMOSPHERIC  PRESSURE 117 

*56.    COLUMNS  OF  MERCURY  AS  INDICATORS  OF  AIR  PRESSURE 119 

*57.    MAKING  A  MERCURIAL  BAROMETER  .         . 121 

58.    THE  ACTION  OF  A  BAROMETER.         .............  128 

*5(J.    CONDITIONS  AFFECTING  EVAPORATION         ............  125 

60.  EFFECTS  OF  EVAPORATION           ..............  125 

61.  CONDENSATION  OF  WATER  VAPOR      .         .         .         .         .         .         .         .         .         .         .         .         .127 

*62.    FORMATION  OF  FOG  AND  CLOUD         .............  129 

63.    MOISTURE  IN  THE  ATMOSPHERE.     RELATIVE    HUMIDITY    .........  131 

04.    MOISTURE  IN  Tin;   A  IM<'-PIII:I:I..      ABSOLUTE  HUMIDITY   .........  134 

65.    EXPERIMENTS  WITH   HEAT  —  A.   EXPANSION  OF  A   SOLID;    B.   EXPANSION  OF  A  LIQUID;    C.   EX- 
PANSION OF  A   GAS;   D.  CONDUCTION;    E.  Co\\i.  TH>N   IN  A   Ligi  n- :     F.    CONVECTION    IN   A 

GAS  ;   G.  RADIATION  ;    II.  ABSORPTION 135 

*66.    RELATIVE  AMOUNTS  OF  HEAT  RECEIVED  i  ROM    rni;  Six           ........  140 

*67.    ELEMENTARY    KXERCISE  ON  ISOTHERMS       ............  1  12 

*68.    DISTRIBUTION  OF  TEMPERATURE         .............  144 

*69.    SEASONAL  RANGE  OF  TI.MI-KK.VTURE.     EFFECT  OF  LATITUDE   ........  14(5 

70.   SEASONAL  RANGE  OF  TEMPERATURE.     EFFECT  OF  L\\n   \\n  SEA 148 

*71.    DAILY  RANGE  OF  TEMPERATURE        .......                  .....  160 

72.  TERRESTRIAL  OR  PLANETARY  WIND  BELTS 151 

73.  FERREL'S  LAW 1..  : 

*74.    WEATHER  MAPS          ................  165 

*75.    WEATHER  RECORD 157 

*76.    THE  TEMPERATE  LATITUDE  CYCLONE         ............  169 

*77.    RAINFALL  IN  THE   I'NITED  STATES     .............  162 

78.  SEASONAL  DISTRIBUTION  01    K\IM  U.L      ............  164 

79.  SEASONAL  DISTRIBUTION  OF  RAINFALL  (Ai>\  ANC -i-:i>)          .........  166 

80.  MAGNETISM.     THE  COMPASS       ..............  167 

THE   OCEAN 

*81.    SECTION  OF  OCEAN  BORDER.     CONTINENTAL  SHI-.LF          .........  169 

82.  SECTION  OF  THE  NORTH  ATLANTIC  OCEAN 172 

*83.  TIDES  IN  THE  (.)<  i  w 174 

*84.  NEW  JERSEY.  ATLANTIC  CITY  Sin  i  r.  A  Low  COAMM.  I'I.AIN 176 

*86.  MAINE.  BOOTHBAY  SHEET.  A  ROCKY  COAST  ..........  178 

86.  OREGON.  PORT  ORFOI:I.  SHEET.  A  NARROW  COASTAL  PLAIN 180 

*87.  WINDS  AND  CURRENTS  ...............  182 

88.  OCEAN  Km  us 184 

*89.  RAINFALL  AND  VEGETATION  ..............  187 

90.    PICTURE  SUPPLEMENT  — RAINFALL  AND  VEGETATION                                                                           .          .  180 


PKEFACE 

THE  exercises  presented  in  this  manual  are  intended  to  be  sufficient  for  a  full  year's  work,  but  they 
are  so  written  that  some  may  be  omitted  by  classes  that  have  not  time  for  all,  without  detriment  to 
those  remaining.  It  is  intended  that  the  pages  of  questions  and  directions  be  bound  with  the  answer 
papers  in  the  notebook.  In  some  exercises  where  the  answers  are  short,  blank  spaces  are  left  on  the 
printed  page  that  the  answers  may  be  written  immediately  after  the  questions.  The  "  loose  leaf  "  plan 
of  binding  gives  opportunity  not  only  for  the  omission  of  exercises  not  needed,  but  also  for  the  inser- 
tion of  such  other  exercises  as  any  teacher  may  choose  to  give.  To  the  same  end,  and  also  that  the 
exercises  may  be  taken  in  the  order  in  which  the  topics  are  studied,  the  exercises  are  not  numbered. 
Reference  may  be  made  to  them  by  the  page  numbers  at  the  bottom  of  the  page.  Pupils  should  pre- 
serve all  their  papers,  and  at  the  end  of  the  course  arrange  them  in  order,  number  the  pages  at  the  top, 
and  write  on  the  Table  of  Contents  sheet  (pp.  191,  192)  the  number,  name,  and  pages  of  each  exercise. 
The  teacher  will  probably  wish  to  examine  and  comment  on  each  exercise  as  soon  as  it  is  done.  The 
binding  margin  is  a  convenient  place  for  marks,  and  also  for  the  pupil's  name,  but  the  pupil  must  be 
careful  not  to  let  his  writing  run  into  this  margin.* 

Some  of  the  exercises  require  heat,  water,  and  considerable  apparatus  —  not  always  to  be  had  at 
each  pupil's  desk.  It  is  suggested  that  such  exercises  be  assigned,  the  day  before  they  are  to  be  done, 
to  several  pupils,  who  shall  have  the  pi'eparations  complete,  and  perform  the  experiments  in  the  presence 
of  the  class.  All  members  of  the  class  should  then  write  up  the  exercise.  Most  of  the  exercises  have 
questions  at  the  end  called  "  Advanced."  These  questions  are  usually  more  difficult  than  those  preced- 
ing, and  are  intended  for  the  rapid  workers  who  finish  the  main  questions  before  the  majority  of  the 
class  are  through. 

A  valuable  service  of  the  geographical  laboratory  is  to  give  concreteness  and  location  to  the  general 
principles  taught  in  the' text-book,  and  so  the  authors  have  tried  in  the  manual  to  cover  nearly  all  the 
topics  treated  in  the  common  text-books  of  physiography.  In  the  selection  of  contour  maps  care  has 
been  taken  to  choose  those  that  clearly  show  the  purpose  of  the  exercise.  Some  of  these  maps,  by  their 
recognized  merit,  have  become  almost  classic ;  it  is  hoped  their  value  will  be  increased  by  the  new  setting 
given  them.  A  certain  uniformity  of  treatment,  suggested  by  the  headings  in  prominent  type,  has  been 
followed  wherever  practicable,  thus  avoiding  a  haphazard  way  of  approaching  the  problem. 

A  Standard  Scale  for  cross  profiles  has  been  used  wherever  possible  in  order  to  simplify  the  com- 
parison of  regions.  The  horizontal  scale  is  the  same  as  that  of  the  sheet  where  the  ratio  is  1/62500, 
and  the  vertical  scale  is  1  cm.  =  100  ft.  This  gives  a  vertical  exaggeration  of  about  twenty.  In 
regions  of  great  relief  a  scale  giving  no  vertical  exaggeration  is  used.  The  great  value  of  the  "  sea- 
level  "  profile  is  to  show  the  altitude  of  the  region.  The  space  between  the  profile  and  the  sea  level 
should  be  shaded,  or  filled  with  the  proper  rock  symbols. 

The  authors  recognize  the  fact  that  the  few  years  during  which  the  laboratory  has  been  used  as  a 
help  in  geography  teaching  have  not  been  sufficient  to  bring  the  methods  to  perfection.  Their  ambi- 
tion has  been,  not  to  write  a  book  that  shall  stand  permanently  as  an  ideal  in  geography  teaching,  but 
to  arrange  some  exercises  that  shall  suggest  better  methods  to  many  teachers,  and  save  time  for  those 
who  are  too  busy  to  work  out  the  details  of  plans  they  may  have  had  in  mind.  Criticisms  and  sugges- 
tions, looking  to  the  elimination  of  errors  or  to  the  introduction  of  new  material,  will  be  welcomed  by 
the  authors.  The  exercises  here  given  have  been  used  in  the  class  room  for  several  years,  and  the 
authors  are  under  obligations  to  their  fellow-teachers  for  many  valuable  suggestions.  The  work  has 
been  tested  in  the  class  room  again  and  again,  rewritten  where  experience  has  shown  it  defective, 
and,  it  is  hoped,  will  now  be  found  suited  to  the  needs  of  the  pupil. 

5 


The  following  Maps  and  Apparatus  are  needed  for  the  full  set  of  exercises  given  in  this  book. 

For  exercises  done  as  demonstrations  before  the  class,  one  set  of  apparatus  will  be  sufficient.  For 
the  exercises  which  each  pupil  is  to  work  out  fully,  all  the  material  required  (globe,  maps,  minerals,  etc.) 
will  be  needed  by  each  pupil. 

Apparatus  marked  with  a  *  will  be  needed  for  the  shorter  course,  and  for  a  class  of  15  pupils  can 
be  secured  at  a  cost  not  to  exceed  $25. 

Topographic  maps,  published  by  the  U.  S.  Geological  Survey,  as  follows :  — 


*  Arizona — Kaibab 
California  —  Cucamonga 

*  Shasta  Special 
Colorado  —  Anthracite 

Lamar 
Illinois  —  Chicago  Folio  No.  81 

*  La  Salle 

*  Ottawa 


Iowa-Illinois  —  Savanna 

*  Kansas  —  Caldwell 

*  Louisiana  —  Donaldsonville 

*  Maine  —  Boothbay 
Maryland-Va.  —  Wicomico 

*  Minnesota  —  St.  Paul 

*  New  Jersey —  Atlantic  City 
New  York —  Niagara 


New  York  —  Watkins 

*  North  Dakota-Minn.  —  Fargo 
Oregon  —  Port  Orf ord 

*  Pennsylvania  —  Harrisburg 

*  West  Virginia  —  Charleston 

*  Wisconsin  —  Whitewater 


Maps  published  by  the  Mississippi  River  Commission,  St.  Louis,  as  follows  :  — 
Sheet  14,  or  Sheet  18,  of  the  Mississippi  River  Survey. 
Map  of  the  Alluvial  Valley  of  the  Upper  Mississippi  River. 
Map  of  the  Alluvial  Valley  of  the  Mississippi  River  from  the  head  of  St.  Francis  IJasiu  to  the  Gulf. 

Pilot  Charts  of  the  North  Pacific      }  , 

,.     Ha  summer  month  and  a  winter  month  ;  pp.  l.jl,  1M). 
Pilot  Charts  of  the  North  Atlantic  j  v 

Bound  sets  of  weather  maps. 


*  Drawing  compasses. 

*  Colored  pencils  or  water  colors. 

*  lluler  marked  in  inches  and  in 

centimeters. 

*  Protractor. 

*  A  six-inch  globe. 

*  A  rubber  band  ^  inch  wide  to 

encircle  the  globe. 
A  horizon  disk  (p.  23). 

*  A  small  ball  with  smooth  un- 

marked surface. 
Copper  or  brass  gauze  (p.  41). 
3  shallow  pans  (p.  :;l). 

1  long  shallow  pan. 
Blotters. 

*  Steel  knitting  needle. 
Sewing  needles. 

*  1  doz.  small  wooden  blocks  one 

inch  thick  (p.  48). 
Metal  ring  and  solid  brass  ball 

(P.  185). 

Metal  rod  two  feet  long. 
Wax  or  paraffin. 
Candle. 

Touch  paper  (p.  137). 
Thread  —  coarse  and  very  fine. 

2  Argand  lamp  chimneys. 

*  Dentists'  rubber. 


*  Small  mirror. 
Bright  tin  cup. 

*  Hand  magnifier. 

*  \  doz.  fi-inch  test  tubes. 
\  doz.  10-inch  test  tul>es. 

:>  large    test    tubes,    perforated 
bottom  (p.  31). 

*  Assorted  glass  tubing. 
*T  tube  \  inch. 

*  Rubber  tubing. 
Glass  funnel. 
Mason  pint  jar. 
Erlenmeyer  fla>k. 

*3  wide-mouth  bottles  with  one- 
and  two-hole  rubber  stoppers. 
Vial. 
Air  thermometer. 

*  Thistle  tube. 

*  Glass  plates. 

*  Glass  tumbler. 
•Glass  cup  (pp.  121,  12:1). 

*  Glass  prism. 

*  Uarometer  tube. 

*  '•'>  His.  mercury. 
2  bar  magnets. 
Iron  filings. 

*  Air  pump  or  bicycle  pump. 
Two-ring  iron  support. 

6 


*  2  thermometers  of  same  >i/e. 
A  chemical  balance. 

*  Limcwater. 
Sodium  peroxide. 
Sulphuric  ether  or  alcohol. 
Potassium  hydroxide. 
I'yrogallic  acid. 
Hyposulphite,  of  soda. 
Alum. 

*  Dilute    hydrochloric  acid,  acid 

bottles,  ami  glass  rod. 
Pieces  of  marble. 

*  Specimens  of  the  following  min- 

erals and  rocks:  quart/,  feld- 
spar, mica,  hornblende,  cal- 
cite.  and  others  if  desired 
(p.  30):  coarse  granite,  gneiss, 
limestone,  marble,  sandstone, 
quartzite,  shale,  slate,  and 
miscellaneous  rocks. 

*  Various  kinds  of  coal. 
Iron  ores  (  p.  :}>'• ). 

Rich  black  soil,  sand,  clay,  un- 
\\i-athered  till. 

*  Glacial    pebbles,    water-washed 

pebbles. 

Molding    sand,    modeling    tool, 
and  sand  tray  (see  p.  }.">). 


A          100        200        800       400 
REFERENCE. 
Over  £000  feet 
4000  to  6000  feet 
2000  to  4000  feet 
1000  to  2000  feet 
Sea  level  to  1000  feet 


110  106  100 


ANMAL  RAINFALL 

OF  THE 
UNITED  STATKS 


110 


105 


A  GL0BE  EXERCISE 

Purpose.     To  study  latitude  and  longitude,  etc.,  on  a  globe  representing  the  rotating  earth. 

Material.     A  small  globe,  a  pair  of  compasses,  a  ball  with  smooth  surface  unmarked. 

Questions  (Answers  to  be  written  on  note  paper  of  about  the  same  size  as  this  sheet;  see  Preface.) 

1.  Has  the  smooth  ball  lying  still  on  the  desk  a  diameter?     A  circumference?     An  axis?     An 
equator?    Poles? 

2.  Spin  the  ball  as  you  would  a  top.     Which  of  the  above-named  features  has  it  acquired  by 
rotation  ? 

3.  What  is  the  name  of  the  line  on  which  the  ball  rotates?    Where  are  the  poles?    Where  is  tin- 
equator? 

4.  On  the  globe  note  two  sets  of  reference  lines  (fine,  black)  drawn  as  a  convenience  in  desig- 
nating the  location  of  places.     In  what  directions  do  these  lines  run  ? 

5.  The  meridians  (north-south  lines)  end  in  what  points? 

6.  They  are  how  many  degrees  long  ? 

7.  How  many  meridian  lines  are  drawn  on  this  globe?     How  many  could  there  be  in  imagina- 
tion ?    Into  how  many  equal  spaces  do  those  drawn  divide  the  surface  of  the  globe? 

8.  How  many  degrees  wide  is  one  of  the  meridian  spaces  ?    How  many  miles  wide  at  the  equa- 
tor?    At  the  pole? 

9.  Set  the  compasses  at  the  width  of  a  meridian  space  at  the  equator.     At  what  latitude  dws  this 
equal  the  width  of  two  meridian  spaces?     How  many  miles  in  the  360  degrees  of  longitude  at  this  lati- 
tude ?     How  many  miles  in  one  degree  of  longitude  here  ? 

10.  The  meridians  are  numbered  along  the  equator.     Beginning  at  the  north,  name  in  order  the 
seas  and  countries  through  which  the  prime  meridian  (numbered  0)  passes.     \Vlial   large  city  lies  on 
the  meridian? 

11.  Place  the  globe  with  the  prime  meridian  toward  you.     Is  east  longitude  toward  your  right 
hand  or  your  left  ? 

12.  Name  in  order,  beginning  at  the  prime  meridian  and  going  east,  the  countries  and  oceans 
crossed  by  the  equator. 

13.  The  distance  between  the  equator  and  the  pole  is  divided  into  how  many  bands  of  equal  width 
by  parallel  circles  around  the  globe?     How  many  degrees  wide  is  each  band? 

14.  From  what  line  is  latitude  reckoned?    What  is  the  greatest  number  of  degrees  of  latitude; 
possible  on  the  globe  ?     At  what  places  ? 

Advanced  Questions.  15.  Suppose  it  is  noon  January  1,  1907,  at  London;  count  eastward  the, 
meridian  spaces  (each  15°  represents  one  hour  in  the  afternoon);  what  is  the  time  at  180°?  Count 
westward  the  time  before  noon;  what  is  the  time  at  ISO0?  What  difference  in  time  do  you  get  at 
180°  by  the  two  counts  ?  The  international  date  line  "  where  the  day  begins  "  follows  the  meridian  of 
180°  in  the  main,  passing,  however,  through  Bering  Strait  and  west  of  the  Aleutian  Islands. 

16.  Find  the  parallel  circles  (drawn  in  broken  lines)  that  mark  the  zone  boundaries,  and  give 
their  names  in  order,  beginning  at  the  north.     How  many  degrees  from  the  equator  to  each  tropic 
circle  ?    To  each  polar  circle  ?    How  many  degrees  wide  is  the  torrid  zone  ?    Each  temperate  zone  ?    1 1«  >\v 
many  degrees  from  the  edge  to  the  center  of  each  frigid  zone  ?    Name  the  waters  and  countries  through 
which  each  zone  boundary  passes. 

17.  Give  the  latitude  and  longitude  of  each  of  the  following  places  :  Washington,  Chicago,  San 
Francisco,  London,  Rome,  Tokio,  Cape  Horn,  Cape  of  Good  Hope,  Cape  Farewell. 


10 


THE  GLOBULAR  PROJECTION  OF  THE  WESTERN  HEMISPHERE 

Purpose.     To  represent  in  a  plane  the  curved  surface  of  half  a  sphere. 

Material.     Drawing  compasses:  a  medium-hard  sharp  pencil,  a  ruler,  a  small  globe. 

On  an  accompanying  sheet  of  paper  is  a  circle  six  inches  in  diameter  to  represent  the  circumference 
of  the  globe,  a  straight  line  to  represent  the  equator,  and  another  at  right  angles  to  this  to  represent  the 
central  meridian.  Through  the  three  points  next  above  the  equator  marked  on  the  central  meridian 
and  on  the  circumference,  draw  an  arc  to  represent  10°  N.  latitude.  Through  the  next  three  points 
draw  another  arc  to  represent  20°  N.  latitude ;  and  so  on. '  These  arcs  may  be  drawn  free-hand,  or,  if  you 
have  a  suitable  compass,  set  one  leg  in  the  line  of  the  central  meridian  extended,  at  a  distance  of  24 
inches  from  the  10?  points  and  draw  the  arc.  For  each  new  arc  you  will  have  to  take  a  new  radius ; 
for  20°  take  llf-inch  radius;  for  30°,  7  inches;  40°,  4^f  inches;  50°,  3$  inches;  60°,  2$  inches;  70°,  1J 
inches ;  80°,  f  inch. 

Draw  the  corresponding  lines  south  of  the  equator. 

For  the  tropical  circles  (latitude  23'°)  use  a  radius  of  9£  inches :  for  the  polar  circles  (latitude  66J°), 
a  radius  of  If  inches.  Draw  colored  or  broken  lines  to  represent  these  circles. 

Through  the  poles  and  each  point  marked  on  the  equator  draw  a  meridian;  free-hand  or  with  com- 
pass (one  leg  in  the  equator  line)  set  as  follows:  for  the  meridian  nearest  the  central.  !<  1-inch  radius; 
for  the  next,  5-inch  radius;  then  3J  inch  ;  3}  inch  ;  and  3^  inch.  If  the  meridians  are  drawn  free-hand. 
draw  the  second  from  the  center  first;  then  the  fourth,  bisecting  the  space  in  \\liicli  it  is  drawn  :  tin- 
first,  third,  and  fifth  each  bisecting  its  space.  Number  the  meridians  along  the  equator,  beginning  at 
the  right  (east),  0°,  15°,  30°,  etc.,  up  to  180°  at  the  west  margin.  Along  the  east  and  the  west  margin 
number  the  parallels  0°,  10°  N.,  20°  N.,  etc.,  and  10°  S.,  20°  S.,  etc.,  and  write  the  names  of  the  tropical 
and  the  polar  circles. 

Find  on  the  globe  the  latitude  and  the  longitude  of  the  south  point  of  Florida,  the  mouth  of  the 
Mississippi  River,  and  the  point  of  Yucatan,  Locate  these  points  on  your  map  by  mean-;  of  your  lati- 
tude and  longitude  lines,  and  with  these  points  for  guides  draw  the  outline  of  the  Gulf  of  .Mexico.  (Jet 
the  latitude  and  the  longitude  of  a  point  in  Nova  Scotia,  in  'Labrador,  etc.  Locate  these  points  on  your 
map  and  sketch  in  the  east  coast  of  North  America.  In  the  same  way  fix  several  guide  points  in  tin- 
west  coast  of  North  America,  and  in  the  coast  of  South  America,  and  complete  the  outline  of  the 
western  continent. 

Questions.  1.  One  half  inch  on  the  equator  of  your  map  represents  Jf  of  the  earth's  circumference ; 
how  many  miles  does  it  represent?  One  half  inch  for  this  number  of  miles  may  be  taken  as  the  scale  on 
which  the  map  is  drawn. 

2.  Will  ^  inch  represent  this  number  of  miles  along  the  central  meridian  ? 

3.  Will  5  inch  represent  this  number  of  miles  along  the  most  easterly  and   the  most  westerly 
meridians? 

4.  The  60°  parallel  on  the  globe  is  just  half  the  length  of  the  equator;  is  the  curved  line  60°  on 
your  map  just  half  as  long  as  the  equator? 

5.  Considering  the  questions  above,  what  parts  of  your  map  are  true  to  the  scale?     What  parts 
are  inaccurate? 

6.  What  angles  do  meridians  make  with  parallels  on  the  globe? 

7.  Where  on  your  map  do  the  meridians  make  this  angle  with  the  parallels? 

8.  On  the  globe,  is  the  distance  between  two  parallel  circles  everywhere  the  same  ? 

9.  Is  it  so  on  your  map  ? 

10.  Hold  your  pencil  along  the  central  meridian  of  your  map.     In  what  direction  does  it  point? 

11.  Slide  the  pencil  slowly  to  the  left  or  right  without  changing  its  direction  on  the  paper;  does  it 
along  its  whole  length  continue  to  point  in  the  same  map  direction  as  at  first? 

12.  Hold  your  pencil  along  the  equator;  in  what  direction  does  it  point? 

13.  Slide  it  slowly  up  or  down  without  changing  its  direction  on  the  paper;  does  it  continue  along 
its  whole  length  to  point  in  the  same  direction  as  at  the  equator? 

Advanced  Questions.  14.  Questions  1  to  9  call  attention  to  inaccuracies  which  cannot  altogether 
be  avoided  in  representing  a  spherical  surface  in  a  plane.  What  are  the  inaccuracies? 

15.    Questions  10  to  13  call  attention  to  inconveniences  in  the  map.     What  are  the  inconveniences? 

12 


13 


MERCATOR'S   MAP  OF  THE   EARTH 

Purpose.  To  draw  a  map  that  shall  represent  the  surface  of  nearly  the  whole  earth,  and  in  which 
the  points  of  the  compass  do  not  shift  in  going  across  the  paper.  (See  questions  10-13  in  the  exercise 
on  the  Globular  Projection  of  the  Western  Hemisphere,  p.  12.) 

Material.    Globe,  ruler,  hard,  sharp  pencil,  drawing  compasses. 

On  the  accompanying  double  sheet  of  paper  is  a  rectangle  drawn  for  the  frame  of  your  map.  Across 
this,  3^  inches  from  the  bottom  (measure  at  both  ends),  draw  a  line  12  inches  long,  to  represent  the 
entire  equator.  Along  the  equator  and  also  along  the  inner  line  at  the  top  and  at  the  bottom  of  the 
frame,  make  a  dot  every  half  inch.  Through  these  dots  draw  lines  to  represent  the  meridians. 

Questions.  1.  How  many  meridian  spaces  are  there  in  the  map?  Therefore,  how  many  degrees 
apart  are  the  meridians  ? 

2.  Reckoning  the  circumference  of   the  earth  as  25,000  miles,  how  many  miles  apart  are   the 
meridians  at  the  equator  ? 

3.  Are  the  meridians  on  the  globe  the  same  number  of  miles  apart  at  10°,  20°,  30°,  etc.,  from  the 
equator? 

Are  they  equidistant  on  your  map  ?  % 

Is,  therefore,  the  scale  at  which  the  map  is  drawn  at  one  latitude  the  same  as  that  at  which  it  is 
drawn  at  another  latitude  ? 

For  this  reason  no  scale  is  commonly  given  for  a  Mercator's  map,  except  sometimes  a  scale  for  the 
equator. 

4.  Imagine  a  circular  island  100  miles  in  diameter  at  the  equator  and  another  of  the  same  size  at 
60°  latitude.     At  60°  latitude  the  meridians  in  Mercator's  map  are  "  stretched  "  apart  to  double  their 
normal   distance.     Into   what  shape,   therefore,   would   the   circle   imagined    at  60°  on  the  earth  be 
"  stretched  "  on  the  map  ? 

5.  How  could  this  figure,  while  keeping  its  double  east- west  size,  be  brought  to  the  form  of  a  circle 
again? 

In  order,  then,  to  represent  on  the  Mercator's  map  small  bodies  of  land  or  water  in  their  true  shape, 
a  band  of  10°  of  latitude  at  60°  from  the  equator  should  occupy  as  much  space  as  20°  along  the  equator. 

The  east-west  "  stretching "  between  meridians  has  been  computed  for  each  10°,  and  the  space 
that  would  normally  be  occupied  by  10°  of  latitude  on  this  map  (£  inch)  has  been  multiplied  by 
this  number,  that  the  north-south  exaggerations  might  equal  the  east-west,  and  so  the  correct  forms 
of  small  areas  be  maintained.  Draw  a  line  for  10°  latitude  ^  inch  from  the  equator,  one  each  side;  for 
20°  draw  a  line  almost  f  inch  from  the  10°  line  (almost  ff  inch  from  equator)  ;  for  30°,  a  very  little 
more  than  f  inch  from  the  20°  line  (1^32  inches  from  equator)  ;  for  40°,  T^  inch  from  the  30°  line  (l£v 
inches  from  equator)  ;  for  50°,  £  inch  from  40°  (2T\  inches  from  equator)  ;  for  60°,  a  little  more  than 
|  inch  from  50°  (a  little  more  than  2f£  inches  from  equator)  ;  for  70°,  one  inch  from  60°  (a  little  more 
than  3|i  inches  from  equator)  ;  for  80°,  a  little  more  than  1}  inches  from  70°  (5^  inches  from  equator). 

6.  Why  not  continue  the  map  to  the  pole? 

The  Arctic  Circle  should  be  drawn  not  quite  £  inch  north  of  60°,  and  the  tropical  circles  less 
than  $  inch  from  20°. 

Sketch  in  the  outlines  of  North  and  South  America,  and  Greenland,  after  having  carefully  located 
their  prominent  points,  as  in  the  Globular  Projection. 

7.  On  the  globe,  how  does  Greenland  compare  in  size  with  South  America?  How  do  they  compare 
on  your  map  ? 

15 


-AS& 

,  ••.'..  .,    •• 


THE  MOLLWEIDK  PROJECTION 

Advanced  Questions.     The  Mollweide  Projection  is  another  means  of  representing  the  entire  surface 
of  the  earth. 

8.  Which  map,  the  Mollweide  or  the  Mercator,  would  be  more  convenient  for  showing  the  directions 
of  wind  and  of  currents  of  water?    Which  would  be  more  useful  to  navigators? 

9.  Which  map  would  be  better  for  showing  comparative  areas  ? 

10.  Although  the  Mollweide  does  not  exaggerate  size  in  any  part,  it  has  what  drawbacks? 


11.   What  part  of  the  Mollweide  has  the  greatest  distortion  of  shape?    What  part  has  least? 


16 


17 


LENGTH    OF    DAY   AND    NIGHT 


Purpose.  To  find  the  number  of  hours  the  sun  is  (a)  above  the  horizon,  and  (6)  below  the  horizon 
at  certain  times  and  places. 

Material.     A  6-inch  globe  and  a  rubber  band  T9jj  inch  wide,  to  encircle  the  globe. 

Place  the  globe  on  the  desk  before  you,  north  pole  tipped  23^°  to  the  right.  Raise  it  to  the  level  of 
your  eyes,  which  will  represent  the  sun.  This  is  the  position  the  earth  has  relative  to  the  sun  March  21. 

1.  Imagine  a  thread  from  the  center  of  the  sun  to  the  center  of  the  earth.     At  what  point  does  it 
pierce  the  earth's  surface? 

This  is  called  the  "  vertical  ray." 

2.  What  angle  does  it  make  with  the  earth's  surface  ? 

3.  With  the  earth's  axis  ? 

4.  How  much  of  the  earth's  surface  is  in  the  sunshine  ?     How  much  in  the  darkness? 

Rotate  the  globe  toward  the  east  (from  your  left  to  right) . 

5.  What  two  places  stay  in  the  line  dividing  sunshine  from  darkness? 

6.  On  which  side  of  the  globe  does  every  city  come  from  darkness  into  the  sunshine  (sunrise)  ? 

7.  On  which  side  does  every  city  go  from  sunshine  into  darkness  (sunset)? 

8.  How  far  across  the  sunshine  area  has  each  city  passed  at  its  noon  ? 

9.  Where  is  every  city  at  midnight? 

Place  the  band  around  the  globe  so  that  the  edge  nearer  the  sun  shall  lie  in  the  line  dividing  sun- 
shine from  shadow. 

10.  If  the  meridians  on  the  globe  are  15°  apart,  how  much  time  does  each  space  between  merid- 
ians represent? 

11.  Each  point  on  the  equator  passes  through  how  many  hours  from  sunrise  to  sunset? 

12.  From  sunset  to  sunrise  ? 

The  space  under  the  band  has  twilight. 

13.  Does  the  band  cover  the  same  number  of  hour  spaces  at  all  latitudes  ? 

14.  In  what  latitudes  is  twilight  very  short? 

15.  In  what  latitudes  very  long? 

In  the  table  given  below  fill  out  the  March  column  for  all  the  places  given.  (Twilight  is  included 
in  night.) 

LENGTHS   OF   DAY   AND   NIGHT 


PLACE                                      LATITUDE 

MARCH  21 

JUNE  21 

DECEMBER  22 

Day 

Night 

Day 

Night 

Day 

Night 

Mouth  of  Amazon  River             0° 

Your  own  city 

Rio  de  Janeiro                       23°  S. 

North  Cape                             71°  N. 

19 


16.  On  what  other  day  of  the  year  will  the  sun  be  above  the  horizon  and  beiow  the  horizon  the  same 
number  of  hours  as  on  March  21  ? 

Remove  the  band  from  the  globe.  Keeping  the  axis  pointing  to  the  same  spot  in  the  heavens  as  in 
the  March  position,  move  the  globe  to  your  left  one  fourth  of  the  way  around  your  head.  This  is  the 
June  position. 

17.  Which  polar  region  is  now  entirely  in  the  sunshine? 

18.  Which  entirely  in  the  shadow  ? 

19.  At  what  latitude  does  the  vertical  ray  touch  the  surface? 

20.  What  angle  does  the  sun's  ray  make  with  the  axis? 

21.  How  many  degrees  past  the  north  pole  does  the  sunshine  reach  ? 

22.  How  many  degrees  does  it  fall  short  of  reaching  the  south  pole  ? 

Place  the  band  around  the  globe  in  the  June  position  so  that  the  edge  nearer  the  sun  shall  lie  in  the 
line  dividing  sunshine  from  shadow.  Fill  the  June  column  in  the  table. 

Remove  the  band.  Keeping  the  axis  pointing  to  the  same  spot  in  the  heavens,  revolve  the  globe 
further  to  the  left,  from  the  June  position  one  half  way  round  your  head.  The  globe  is  now  in  tin- 
December  position. 

23.  Which  polar  region  is  entirely  in  the  sunshine  ? 

24.  Which  in  shadow? 

25.  At  what  latitude  does  the  vertical  ray  strike  the  surface? 

26.  How  many  degrees  past  the  south  pole  does  the  sunshine  reach  ? 

27.  How  many  degrees  does  it  fall  short  of  reaching  the  north  pole? 

Place  the  band  around  the  globe  to  represent  the  December  position,  and  fill  the  December  column  in 
the  table. 

Fill  the  blanks  in  the  following  general  statements,  and  cross  out  in  each  pair  the  word  which  is 
incorrect. 

At  the  equator  all  days  are hours  long. 

The  higher  the  latitude,  the  longer  shorter  the  summer  day,  and  the  longer  shorter  the  winter  day. 

On  March  21  and  September  23  all  places  have  equal  unequal  day  and  night  of hours. 

The  lower  the  latitude,  the  longer  shorter  the  twilight. 


20 


SUNRISE    AND   SUNSET    GRAPHS 


Purpose.  To  study  and  compare  graphically  the  lengths  of  day  and  night  through  the  year  at  differ- 
ent latitudes. 

Copy  the  following  general  statement,  using  the  correct  word  only  of  each  pair  and  filling  the  blanks :  — 
A  place  nearer  the  equator  has  a  longer  shorter  day  in  winter  and  a  longer  shorter  day  in  summer  than  a 

place  farther  from  the  equator.  About (date)  the  nights  and  days  are  equal  and (number) 

hours  long. 

Write  the  numbers  of  the  twenty-four  hours  of  the  day  (12, 1,  2,  3,  etc.)  along  the  binding  border  of 
a  sheet  of  cross-section  paper  (end  of  this  book),  each  number  at  the  end  of  a  heavy  line,  beginning  and 
ending  with  midnight.  At  one  end  of  the  sheet  write  the  names  of  the  months  on  twelve  consecutive 
heavy  lines.  From  the  table  given  below,  choose  the  latitude  nearest  that  of  the  place  in  which  you  live, 
and  find  the  time  of  sunrise  January  first.  On  the  January  line  of  the  cross-section  paper  make  a  dot  in 
the  place  that  indicates  the  given  time  of  sunrise.  Find  the  time  of  sunset  for  the  same  day  and  make  a 
dot  in  the  proper  place  on  the  January  line.  The  space  between  the  dots  shows  the  length  of  day.  From 
the  table  get  the  times  of  sunrise  and  sunset  on  the  first  day  of  February,  and  make  dots  on  the  February 
line  in  the  proper  places  for  these  times.  Do  the  same  for  each  month.  Draw  a  line  connecting  the  sun- 
rise dots  and  another  connecting  the  sunset  dots.  The  space  between  these  lines  represents  day,  the 
space  outside  of  them,  night. 

Questions.     1.     About  what  time  of  the  year  is  the  day  longest  ?    How  many  hours  long  ? 

2.  About  when  is  it  shortest?    How  many  hours? 

3.  At  about  what  date  does  the  sunrise  graph  cross  the  6  A.M.  line  ?    When  does  the  sunset  graph 
cross  the  6  P.M.  line  ? 

On  the  same  paper  draw  sunrise  and  sunset  graphs  for  St.  Petersburg,  —  using  a  colored  pencil  or 
dash  lines  to  distinguish  from  the  graphs  first  drawn. 

4.  About  what  time  of  year  is  the  day  longest  ?    How  many  hours  long? 

5.  About  when  is  it  shortest?    How  many  hours? 

6.  When  does  the  sunrise  graph  cross  the  G  A.M.  line?    When  does  the  sunset  graph  cross  the 
6  P.M.  line  ? 

7.  Which  of  the  two  places  has  the  longer  summer  day?    Which  has  the  longer  winter  day? 

8.  On  what  date  does  the  graph  of  one  place  cross  that  of  the  other;   i.e.  when  is  sunrise  or  sunset 
for  the  two  places  at  the  same  hour  ? 

Be  sure  each  graph  is  labeled  at  the  end  with  the  latitude  of  the  place  it  represents. 

Advanced  Questions.  Draw  the  graphs  for  82°  N.  (Fort  Conger),  continuing  the  lines  till  they  meet 
at  about  noon  in  February  and  in  October,  and  until  they  reach  midnight. 

The  opening  between  the  lines  at  midnight  means  continuous  day.  About  how  long  is  it?  About 
how  long  is  the  continuous  night  (indicated  on  the  noon  hour)  ? 

Draw  as  many  other  graphs  as  you  have  time  for. 

MEAN   LOCAL  TIME  OF  SUNRISE  AND  SUNSET.     1899 


PLACE 

PARA  0° 

CANCER  28J°  N. 

(111,    V,. 

K  i     < 

CAPE  TOWN 
Uf  - 

SUN 

Rise 

Set 

BtM 

Set 

Rise 

Set 

Rise 

Bet 

Rise 

Set 

BtM 

Set 

January  1        ... 

6:00 

6:08 

6:41 

5:27 

7:28 

4:40 

9:02 

3:06 

4:52 

7:16 

February  1      ... 

6:10 

6:18 

6:40 

5:49 

7:12 

.-,:  11; 

8:15 

4:13 

6:  M 

7:06 

March  1  • 

6:09 

C,:  1(1 

6:21 

6:04 

6:34 

5:51 

6:55 

5:30 

8:55 

3:34 

5:48 

6:36 

April  1     .... 

6:00 

(5  :  07 

5:52 

6:16 

r.  :  4-J 

6:21 

5:24 

6:45 

3:50 

8:25 

6:12 

5:55 

May  1       .... 

5:53 

6:00 

5  :  '_'<! 

6:28 

4:55 

6:69 

7:.  71 

6:35 

-,:  I'.l 

June  1      •        •        •        . 

5:54 

6:01 

5:14 

6:42 

4:25 

7:30 

2:48 

9:08 

6:57 

4  :  .V.) 

July  1       .... 

6:00 

6:08 

5:17 

r,  :  no 

4:28 

7:40 

2:40 

9:26 

7:06 

5:01 

August  1           ... 

6:02 

6:10 

5:29 

(1:4:; 

4:52 

7:20 

8:86 

8:34 

6:53 

r.  :  'JO 

September  1    • 

5:56 

6:03 

5:42 

<i:  IS 

5:25 

<;  :  ;i4 

4:50 

7:10 

1:45 

10:00 

6:  l* 

.-.  :  4'_' 

October  1        ... 

5:46 

5:53 

5  :  51 

5:48 

5:57 

0.-4J 

6:03 

5:36 

6:40 

4:55 

5:37 

6:03 

November  1     .        .        . 

5:40 

5:48 

6:05 

5:33 

6:33 

\  :  54 

7:24 

4:04 

5:00 

6:28 

December  1     • 

5:46 

5:54 

6:25 

5:14 

7:09 

4:30 

8:35 

3:03 

4:40 

6:58 

22 


THE  PATH  OF  THE  SUN 

Purpose.  To  see  how  the  sun  appears  to  move  through  the  heavens  during  the  day  at  different 
latitudes  and  seasons. 

Material.  A  six-inch  globe  with  pin  holes  along  longitude  180°  at  the  latitudes  given  below ;  a  disk 
one  inch  in  diameter  with  two  diameters  drawn  at  right  angles  and  marked  at  the  ends  N.,  E.,  S.,  W.,  and 
through  whose  center  a  pin  is  thrust  to  its  middle ;  a  single  bright  light  in  a  room  otherwise  darkened. 

Prick  no  holes  in  the  globe,  but  put  the  pin  holding  the  disk  into  a  hole  already  made  at  longitude 
180°,  latitude  0°.  Be  sure  the  X.  is  to  the  north.  The  pin  represents  you,  the  disk  your  horizontal 
plane.  Turn  your  back  to  the  light  which  is  to  represent  the  sun  ;  hold  before  you  in  the  light  the 
globe,  in  the  March  21st  position,  i.e.  north  pole  tipped  23£°  to  the  right.  Have  the  disk  on  the  dark 
side  of  the  globe ;  rotate  the  globe  slowly  counterclockwise.  When  you  (the  pin)  reach  the  sunrise 
line,  the  light  will  first  fall  on  the  surface  of  the  disk  and  your  shadow  will  appear. 

1.  In  what  direction  does  the  shadow  extend  ? 

N 

2.  In  what  direction,  then,  is  the  rising  sun  ? 

3.  As  the  globe  slowly  rotates  observe  the  movement  of  your  shadow.      Where  is  it  at  noon  ? 

4.  Where,  then,  is  the  sun  at  noon? 

5.  What  is  the  direction  of  the  setting  sun  ? 

6.  On  what  other  date  does  the  sun  move  through  the  heavens  in  the  same  path  as  on  March  21  ? 

Holding  the  globe  in  the  same  place  change  it  to  the  June  position,  i.e.  north  pole  tipped  23j° 
toward  you.  Beginning  with  the  disk  in  the  shadow,  rotate  as  before. 

7.  Does  the  sun  rise  north,  or  south,  of  east? 

8.  At  noon  is  the  sun  north,  or  south,  of  overhead  (zenith)  ? 

9.  Does  the  sun  set  north,  or  south,  of  west? 

Holding  the  globe  in  the  same  place,  shift  it  to  the  September  position,  the  north  pole  tipped  to 
the  left.  Rotate  as  before. 

10.  What  is  the  direction  of  the  rising  sun? 

11.  Of  the  sun  at  noon  ?     Of  the  setting  sun? 

Shift  the  globe  to  the  December  position,  north  pole  tipped  23£°  from  you. 

12.  Does  the  sun  rise  north,  or  south,  of  east? 

13.  At  noon 4s  the  sun  north,  or  south,  of  the  zenith  ? 

14.  Does  the  sun  set  north,  or  south,  of  west  ? 

In  each  column  of  the  table  below  write  the  direction  of  the  sun  in  0°  latitude. 


DIRECTION  OF   SUN  AT   RISING,   AT  NOON,    AT   SETTING 


MARCH  21 

JUNE  21 

DECEMBER  22 

Rising 

Noon 

Setting 

Rising 

Noon 

Setting 

Rising 

Noon 

Setting 

Equator     .... 

Your  city 

23°  8.          .... 

71°  N. 

23 


Move  the  pin  with  the  disk  to  the  latitude  of  your  own  city.  Find  the  directions  of  (In-  sun  morn- 
ing, noon,  and  evening  in  March,  June,  and  December,  and  fill  blanks  in  the  table. 

Move  the  pin  and  disk  again  to  latitude  23°  S.  Find  the  directions  of  the  sun  as  before  and 
write  in  the  table. 

Repeat  the  study  for  latitude  71°  N. 

15.  At  places  far  north  from  the  equator  does  the  sun  rise  in  June  more,  or  less,  north  <>!'  <-a>! 
than   at  the  equator? 

16.  In  December  more,  or  less,  south  of  east  than  at  the  equator? 

17.  If  the  sun  rises  north  of  east,  where  will  it  set?     If  it  rises  south  of  east,  where  will  it  set? 

General  statements  of  the  directions  of  the  rising  and  setting  sun,  etc.,  may  be  made,  similar  to  the 
general  statements  at  the  end  of  the  exercise  on  .Length  of  Day  and  Ni-ht.  p.  20. 

In' the  recitation  following  this  exercise,  the  pupil  should  be  required  to  indicate,  with  a  pointer 
moving  steadily  at  arm's  length,  the  path  of  the  sun  through  the  sky  on  the  days  and  at  the  latitudes 
given. 


24 


STANDARD   TIME 

Purpose.     To  study  the  time  belts  commonly  employed  in  the  United  States. 

Questions.     1.   How  many  hours  is  75°  W.  longitude  different  in  time  from  London  ?    When  it  is 
noon  at  London,  what  time  is  it  at  this  meridian? 

On  a  blank  United  States  map  (p.  193)  draw  this  line,  75°  W.,  heavy  with  ink  or  colored  pencil. 

2.  Name  a  large  city  lying  near  this  longitude. 

3.  When  it  is  noon  at  London,  what  time  is  it  at  90°  W.  ? 

Draw  this  meridian  as  you  did  the  75th. 

4.  Name  three  large  cities  near  it. 

5.  When  it  is  noon  at  London,  what  is  the  hour  at  the  105th  meridian  west?    Draw  this  meridian. 

6.  Name  a  large  city  near  it. 

7.  When  it  is  noon  at  London,  what  is  the  hour  at  the  120th  meridian  west?    Draw  this  meridian. 

8.  Name  a  large  city  near  it. 

The  meridians  mentioned  above  are  the  centers  of  the  four  time  belts  of  the  United  States. 

9.  How  much  does  each  differ  from  its  neighbor  in  time? 

Theoretically,  the  division  lines  between  the  time  belts  should  be  halfway  between  these  meridians. 
Draw  light  lines  to  mark  their  positions,  67$°  W.,  82J0  W.,  etc.  At  the  north  border  write  the  names  of 
the  time  belts;  east  of  67J°  W.  is  Atlantic  Time  (used  in  the  eastern  part  of  Canada  and  Newfound- 
land) ;  then  Eastern  Time,  Central  Time,  Mountain  Time,  Pacific  Time. 

Practically, the  railroads  regulate  the  time  and  make  the  hour  changes  to  suit  their  convenience  at 
the  ends  of  railroad  divisions.  Draw  heavy  lines  through  the  point-  named  below,  and  you  will  have 
approximately  the  standard  time  boundaries  as  they  are  practically  n-^l. 

Between  Eastern  and  Atlantic  Time  —  the  eastern  boundary  of  Maine. 

Between  Eastern  and  Central  Time  —  from  Port  Arthur  tlmm-h  Lake  Superior  and  Lake  Huron  to 
Detroit,  to  Buffalo  (keeping  north  of  Lake  Erie),  to  Erie,  Pittsburg,  Parkersburg,  Asheville,  Atlanta, 
Augusta,  Savannah. 

Between  Central  and  Mountain  Time  —  Qu'Appelle,  Bismarck,  North  Platte,  Dodge,  El  Paso. 

Between  Mountain  and  Pacific  Time  —  Calgary,  Boise,  Reno,  El  Paso. 

Advanced  Questions.  10.  Why  is  Mountain  Time  omitted  on  the  Southern  Pacific  Railroad  ip 
Texas  and  New  Mexico? 

11.  Why  in  Nevada  does  Mountain  Time  extend  almost  to  the  120th  meridian? 

> 

12.  Why  does  the  Central  belt  extend  so  far  west  of  its  theoretical  boundary  ? 

13.  Why  do  southern  Georgia  and  Florida  have  Central  Time  rather  than  Eastern  ? 


26 


THE   PHASES   OF  THE   MOON 

Purpose.     To  study  the  changes  in  appearance  which  the  moon  undergoes  during  the  month. 

Material.     A  small  globe. 

Let  some  object  at  the  front  of  the  room  represent  the  sun,  your  head  the  earth,  the  globe  the  moon. 
Holding  the  globe  at  arm's  length,  turn  yourself  slowly  once  around  to  the  left;  the  top  of  your  head 
represents  the  north  pole ;  the  globe's  movement  represents  the  course  of  the  moon  around  the  earth. 

Hold  the  globe  a  little  north  or  south  (above  or  below)  of  the  line  from  the  earth  to  the  sun ;  it  is 
now  new  moon. 

Questions.  1.  About  what  fraction  of  the  moon's  surface  is  lighted  by  the  sun?  Can  you,  the 
earth,  see  the  light  part  ? 

2.  Imagine  the  earth  rotating  on  its  axis.     At  what  time  of  day  does  the  moon  rise  (i.e.  appear  in 
the  east  on  the  horizon)  ?     When  does  it  set  ? 

What  is  its  direction  at  noon?     At  midnight? 

Move  the  globe  through  one  fourth  of  its  orbit  —  one  week's  time. 

3.  How  much  of  the  illuminated  half  do  you  see  ? 

4.  When  does  the  moon  rise  ?    When  set?    What  direction  is  it  in  the  morning?    In  the  evening? 

Revolve  the  moon  through  another  fourth  of  its  orbit.     It  is  now  called  "  full." 

5.  How  much  of  its  illuminated  half  do  you  see? 

6.  When  does  it  rise?    When  set?    Where  is  it  at  noon?     At  midnight  V 

Revolve  the  moon  through  the  third  fourth  of  its  orbit. 

7.  Make  four  sketches  (name  each)  to  show  the  form  of  the  bright  moon  at  each  quarter;  mark  tin- 
east  side  E.  and  the  west  side  W. 


Advanced  Questions.  8.  At  one  end  of  a  sheet  of  note  paper  write  an  S  to  represent  the  sun.  <)n<- 
and  one  half  inches  from  the  other  end,  write  E  for  the  earth  ;  to  represent  the  moon's  orbit,  draw  a 
circle,  one  inch  radius,  around  E.  Indicate  the  position  of  the  moon  at  each  quarter.  Name  all  parts 
of  the  diagram. 

9.  During  the  first  and  fourth  quarters  the  moon  is  crescent ;  during  the  second  and  third  quarters 
it  is  gibbous.     Sketch  each  form. 

10.  If  you  hold  the  moon  firmly  in  your  hand  during  its  revolution,  does  it  rotate  on  its  axis'.'     I),, 
we  ever  see  more  than'  one  side  of  the  moon  ? 


28 


PRELIMINARY    STUDY   OF   MINERALS 

Purpose.     To  learn  the  appearance  of  minerals  in  granite. 

Material.  Labeled  specimens  of  clear  quartz,  gray  or  pink  feldspar,  black  mica,  and  hornblende,  and 
a  piece  of  coarse  granite. 

Questions.  1.  Judging  from  color  alone,  how  many  different  substances  do  you  find  in  the  piece  of 
granite  ? 

2.  Are  the  different  colors  of  the  grains  quite  distinct,  or  do  the  colors  blend  into  one  another? 
Allowing  for  difference  in  size,  are  the  grains  as  distinct  as  in  the  mineral  specimens  you  have  when 
held  together  in  the  hand  ? 

3.  Describe  the  grains  that  most  closely  resemble  the  quartz  specimen  by  telling  whether  they  are 
shiny,  dull,  smooth,  rough,  etc.     What  common  substance  do  these  grains  resemble? 

4.  Describe  in  a  similar  way  the  grains  that  most  closely  resemble  the  specimen  of  feldspar. 

5.  Do  you  find  any  grains  in  the  granite  that  closely  resemble  the  mica  or  the  hornblende  ?    If  so, 
how  do  you  distinguish  them  ? 

6.  Make  a  list  of  the  minerals  that  appear  to  be  in  the  granite. 

i 

THE    STUDY   OF   MINERALS 

Purpose.  The  mineral  specimens  used  in  the  previous  exercise,  together  with  calcite,  gypsum,  rock 
salt,  kaolin,  and  a  few  others,  are  among  the  most  important  minerals  in  the  formation  of  rocks.  These 
minerals  may  be  more  fully  studied  by  using  the  following  outline  :  — 

1.  Name.     Give  the  name  of  the  mineral. 

2.  Color.     Give  the  color  or  colors  of  the  mineral. 

3.  Transparency.     Minerals  are  (a)    transparent,  when  clear   like  window  pane;  (b)  translucent, 
when  a  small  amount  of  light  gets  through,  as  through  a  window  shade ;  (c)  opaque,  when  no  ligltt 
goes  through.     Hold  your  mineral  toward  a  window  and  decide  as  to  its  transparency. 

4.  Hardness.     Minerals  and  rocks  are  (a)  very  soft,  if  easily  scratched  with  thumb  nail ;  (fc)  soft, 
if  easily  scratched  with  steel  rod;  (c)  hard,  if  scratched  with  diflirnlty  with  steel;  (//)  very  hard,  if 
they  cannot  be  scratched  with  steel.     Test  your  mineral  in  the  above  order  and  record  its  hardness. 

5.  Acid  Test.     Put  a  drop  of  hydrochloric   acid  on  the  mineral  and  watch   the  effect.     If  the 
mineral  is  affected,  bubbles  of  gas  will  be  formed.     Give  the  result  of  your  test. 

6.  Porosity.     A  dry  mineral  is  porous,  if  a  drop  of  water  or  acid  sinks  rapidly  into  it.    It  is  compact, 
if  the  drop  remains  for  some  time  on  the  surface.     Test  your  mineral  and  toll  whether  it  is  porous  or 
compact. 

7.  Durability.     The  durability  of  a  mineral  depends  very  largely  ii]»ni  its  hardness,  its  resistance  to 
acid,  and  its  porosity.     As  you  have  already  made  these  testa,  tell  why  you  think  the  mineral  would 
make  a  weak  or  a  durable  part  of  a  rock. 


30 


THE    STUDY   OF   ROCKS 

Purpose.  The  different  rocks  composing  the  crust  of  the  earth  are  either  igneous  rocks  or  rocks  derived 
from  igneous  rocks  by  the  action  of  such  forces  as  the  weather,  great  heat  and  pressure,  and  chemical 
agencies.  The  following  studies  are  intended  to  emphasize  the  important  properties  of  the  common 
rocks,  such  as:  I.  Igneous  rocks  (granite  and  gneiss),  II.  Calcite  rocks  (limestone  and  marble),  III. 
Clay  rocks  (shale  and  slate),  IV.  Quartz  rocks  (sandstone  and  quartzite),  V.  Miscellaneous  rocks. 

I.  Granite  and  Gneiss.  Granite  results  from  the  slow  cooling  of  lava  under  heavy  pressure.  Gneiss 
is  composed  of  the  same  minerals  as  granite,  but  is  coarsely  banded,  a  structure  probably  due  to  a  re- 
arranging of  the  minerals  iu  granitic  rocks. 

1.  What  is  the  general  color  of  the  granite  ? '   Of  the  gneiss  ? 

2.  How  are  the  minerals  arranged  in  the  granite  ?    In  the  gneiss  ? 

3.  Name  and  give  the  color  of  the  different  minerals  found  in  each  rock. 

4.  .Tell  the  shape  of  the  grains,  whether  rounded  or  angular. 

5.  Could  the  grains  have  been  collected  by  running  water  and  bound  together  as  you  see  them 
here  ?     Give  a  reason. 

6.  How  does  a  drop  of  acid  act  when  put  upon  each  rock  ? 

7.  How  hard  is  each  rock  as  shown  by  steel-rod  test? 

8.  Which  rock  do  you  think  is  better  for  buildings  and  monuments,  and  why? 

II.  Limestone  and  Marble.     When  granite  rocks  decay,  certain  minerals,  especially  feldspar,  yield 
lime,  which,  uniting  with  carbon  dioxide,  produces  calcite  or  limestone.     Marble  is  a  crystalline  rock 
resulting  from  changes  in  beds  of  limestone. 

1.  What  is  the  color  of  the  limestone?    Of  the  marble  ? 

2.  How  do  the  two  rocks  compare  in  hardness?     Are  they  soft  or  hard? 

3.  Describe  the  action  of  acid  upon  limestone ;  upon  marble.     If  the  action  is  very  slow,  the  rock 
is  probably  dolomite  (one  containing  some  magnesium  carbonate). 

4.  Do  you  find  any  fragments  of  shells  in  either  rock  ?     If  so,  describe  them. 

5.  Which  rock  would  make  a  better  interior  finish?     Which  is  more  extensively  used  for  outside 
work?     Why? 

6.  If  the  surface  rocks  of  a  region  consist  of  masses  of  granite  and  limestone,  which  would  weather 
the  more  rapidly  and  so  form  valleys  ?     Which  would  form  the  ridges  and  hills  ?     Give  a  reason  for 
your  answer. 

III.  Shale  and  Slate.     Another  product  of  the  decomposition  of  feldspar  and  similar  minerals  is 
mud  or  clay  (kaolin).     This  fine  material  is  carried  into  the  sea,  and  there  by  moderate  heat  and  pres- 
sure may  be  made  into  shale.     Greater  heat  and  pressure  will  produce  slate. 

1.  What  is  the  color  of  the  shale ?     Of  the  slate? 

2.  Which  rock  has  the  smoother  and  softer  feel? 

3.  Can  you  scratch  either  rock  with  the  thumb  nail?     Determine  by  other  tests,  if  necessary,  which 
is  the  harder  rock. 

4.  Examine  the  rocks  with  the  magnifier.     Can  you  see  the  grains  distinctly  in  either  ?    Why  ? 

5.  How  does  a  drop  of  acid  act  when  put  upon  each  rock? 

6.  Which  rock  do  you  think  would  be  more  easily  affected  by  rain  and  frost  ?    Why  ? 

7.  Why  can  slate  be  used  for  blackboards  and  roofing,  and  not  shale? 

8.  If  a  level  region  consisting  of  granite,  limestone,  and  shale  is  exposed  for  a  long  time  to  the 
weather,  which  of  the  rocks  would  probably  form  the  ridges  and  which  the  valleys?     Why? 

IV.  Sandstone  and  Quartzite.     When  granite  decomposes,  quartz  alone  remains  unaltered.     Grains 
of  quartz  are  collected  by  running  water  and  bound  together  by  a  cement  into  sandstone.     The  cement 
is  probably  carbonate  of  lime,  if  white  or  gray,  and  iron  oxide,  if  yellow  or  brown.     Quartzite,  in  which 
silica  is  the  cement,  has  been  formed  by  pressure,  heat,  and  chemical  changes  in  beds  of  sandstone. 

1.  What  is  the  color  of  the  sandstone?     Of  the  quartzite ? 

2.  From  which  can  you  loosen  grains  the  more  readily  with  the  steel  rod  ?    Which,  therefore,  is 
the  firmer  rock  ? 

3.  Examine  both  rocks  with  the  magnifier.     In  which  can  the  grains  be  more  easily  seen?    What 
is  the  reason  ? 

31 


4.  How  does  a  drop  of  acid  act  when  put  upon  each  rock?     In  what  way  does  this  test  determine 
relative  compactness? 

5.  From  what  yon  know  about  cements,  which  kind  do  you  think  holds  the  grains  together  in  the 
sandstone? 

(i.    Which  rock  would  make  a  better  building  stone?     Which  is  more  commonly  used ?     Why? 

7.  If  masses  of  granite,  limestone,  shale,  and  sandstone  compose  the  surface  rock  of  a  region,  which 
of  them  would  in  time  form  valleys  and  which  hills?  Why? 

V.  Miscellaneous  Rocks.  If  it  is  desirable  to  study  other  kinds  of  rocks,  the  following  questions 
may  be  used :  — 

1.  Give  name  and  color  of  the  rock. 

2.  Describe  the  structure,  whether  (a)  fine  or  coarse,  (ft)  porous,  cellular,  or  compact,  (c)  uniform, 
banded,  or  stratified. 

3.  Has  the  rock  a  smooth  or  a  gritty  feel  ?     A  bright  or  a  dull  lust*  r  ? 

4.  Is  its  weight  light,  medium,  or  heavy? 

5.  How  hard  is  the  rock  ? 

6.  How  does  a  drop  of  acid  act  when  put  upon  the  rock  ? 

7.  What  minerals  can  you  find  in  the  rock? 

8.  For  what  uses  is  the  rock  well  adapted  ?     Why  ? 

Porosity  of  Rocks.  lu  connection  with  the  study  of  rocks  the  following  test  of  their  porosity  may 
be  made :  — 

Take  samples  of  dry  granite,  sandstone,  limestone,  and  shale  of  about  equal  size  (as  large  as  a 
walnut)  and  weigh  each  carefully.  Put  them  into  a  dish  of  water,  and  after  two  or  three  days  take  them 
out,  wipe  off  the  surface  water,  and  weigh  them  again.  From  these  weighings  determine  the  relative 
porosity. 

Fill  out  a  table  like  the  following  :  — 


NAME  OF  ROCK 

DRY  WEIIUIT 

WET  WEICIIT 

:KA8B 

I'F.IK-KNTAGK  or  INCREASE 

32 


COMPOSITION   OF   SOIL 

Purpose.     To  study  the  composition  of  soil. 

Material.  A  sample  of  moist  soil,  a  hand  magnifier,  a  glass  plate,  dilute  hydrochloric  acid,  a 
closed  vial  containing  £  inch  of  the  soil  and  not  quite  filled  with  water,  three  shallow  pans,  some  sand 
and  some  clay,  and  an  apparatus,  described  below,  for  testing  the  porosity  of  soils. 

Questions.     1.    What  is  the  general  color  of  the  soil? 

2.  Put  a  little  of  the  soil  on  the  glass  plate  and  examine  it  with  the  magnifier. 

(a)  Do  you  find  any  pebbles  or  fragments  of  rock  ?     If  so,  give  their  sizes,  shapes,  and  kinds. 

(6)  Do  you  find  any  grains  of  sand  ?     If  so,  give  their  colors  and  shapes. 

(c)  Do  you  find  any  rock  waste  finer  than  sand?    If  so,  by  what  name  is  it  generally  known? 

((/)  Put  a  drop  of  acid  upon  the  soil.     What  does  the  test  show  ? 

(e)  Look  for  vegetable  matter,  such  as  roots,  bits  of  leaves,  bark,  or  stems.  Describe  what  you 
find,  and  tell  whether  the  amount  is  large  or  small. 

(/")  Do  you  find  any  fragments  of  shells?    If  so,  describe  them. 

(<7)  If  you  find  any  seeds,  describe  their  appearance.  (The  seeds  are  probably  from  weeds,  and 
would  grow  under  favorable  conditions.) 

(A)  Describe  any  other  substances  you  find  in  the  soil. 

3.  Carefully  examine  the  vial  containing  soil,  and  make  a  drawing  of  it.     Label  the  different  parts 
of  the  contents. 

4.  Gently  shake  the  vial  until  all  the  soil  is  in  suspension,  then  place  it  upon  the  table  and  observe 
what  part  settles  first,  what  next,  and  so  on,  and  what  floats.     Describe  the  order  in  which  the  various 
parts  settle. 

5.  The  apparatus  for  showing  porosity  of  soil  consists  of  three  or  more  large  test  tubes  with 
small  holes  in  the  bottom,  stopped  with  cotton  to  prevent  the  soil  from  running  through.     These 
test  tubes  are  fastened  to  a  stand  and  nearly  filled  with  different  kinds  of  soil,  one  with  clay,  one  with 
sand,  one  with  soil  under  examination,  etc.     Pour  water  into  the  tubes  and  com  pan-  tin-  number  of 
drops  that  fall  from  each  in  two  or  three  minutes.      How  do  the  soils  compare  with  each  other  in 
porosity  ? 

6.  Will  the  soil  under  examination  allow  air  and  water  to  enter  it  readily?    Why?    Would  it 
be  called  light,  medium,  or  heavy? 

Advanced  Questions.  7.  Name  the  different  rocks  that  may  have  contributed  to  the  formation 
of  this  soil. 

8.  Put  a  quantity  of  sand  into  one  of  the  large  pans,  day  into  another,  and  the  soil  under 
examination  into  a  third.  Wet  all  thoroughly  and  stir  one  half  of  each  sample  with  a  stick,  leaving 
the  other  half  undisturbed.  Set  them  aside  for  a  few  days,  and  when  they  are  fully  dr\.  examine 
them  to  see  whether  the  soils  "  cake  "  and  how  they  are  affected  by  working  them  when  wet.  Write  a 
full  description  of  this  operation  and  the  results. 


34 


IRON    COMPOUNDS 

Purpose.     To  study  some  of  the  important  compounds  of  iron. 

The  principal  ores  from  which  iron  is  obtained  are  (1)  Hematite  (Fe.,0.,),  (:.')  Ma^m-tite  (Fe3O4), 
ami  (:!)  Limonite  ('2  Fe2O3,  3  H2O).  The  first  two  contain  about  70%  of  iron  and  the  last  about  (in 

Iron  pyrites  (FeS.,),  "fools'  gold,"  has  a  brass-yellow  color  with  ;i  metallic  luster,  and  the  crystals 
are  often  cubical.  This  mineral  is  of  no  value  as  a  source  of  iron,  as  the  sulphur  cannot  be  entirely 
driven  off.  It  is  of  importance,  however,  as  a  source  of  sulphuric  acid  and  sulphate  of  iron. 

A.  Library  Work.     The  pupils  should  consult  works  of  reference,  such  as  Census  Reports,  Geolo- 
gies, and  Commercial  Geographies,  to  find:  — 

1.  Location  of  large  deposits  of  iron. 

'2.  How  the  ore  is  mined,  where  it  is  marketed,  and  ho\v  it  is  smelted. 

3.  How  cast  iron,  wrought  iron,  and  steel  are  made. 

4.  The  advantages  of  finding  iron  ore,  coking  coal,  and  limestone  together,  as  in  Alabama. 

5.  What  three  states  lead  in  the  manufacture  of  iron,  and  why? 

6.  The  commercial  importance  of  iron  products. 

B.  Laboratory  Work.     The  pupil  should  examine  as  many  different  kinds  of  iron  ore  as  possible 
and  for  each  kind  determine  the  following  properties:  — 

1.  Color. 

2.  Luster. 

3.  Hardness. 

4.  Color  of  the  streak  made  by  rubbing  the  ore  on  rough  paper. 

5.  Effect  of  acid. 

6.  Whether  the  weight  is  light,  medium,  or  heavy. 


COAL 

Purpose.     To  study  the  characteristics  of  coal.     The  coal  series  comprises  (1)  Peat,  (2)  Lignite, 
(3)  Bituminous  coal,  (4)  Anthracite,  (5)  Graphite. 

A.  Library  Work.     The  pupil  should  consult  works  of  reference  on  coal  (see  under  Iron  Com- 
pounds) to  learn  :  — 

1.  The  origin  of  each  kind  of  coal. 

2.  The  kinds  of  rock  associated  with  coal. 

3.  The  location  of  large  coal  fields  in  the  United  States. 

4.  The  three  leading  states  engaged  in  the  mining  of  coal. 

5.  The  coking  of  coal  and  the  use  of  coke. 

6.  The  industrial  use  of  each  kind  of  coal. 

7.  The  output  of  coal  in  the  United  States  as  compared  with  the  rest  of  the  world. 

B.  Laboratory  Work.     The  pupil  should  examine  specimens  of  as  many  kinds  of  coal  as  possible, 
also  partly  burned  pieces  of  anthracite,  to  see  the  structure.     Then  a  description  of  each  coal  should  be 
written,  giving  :  — 

1.  Color. 

2.  Luster. 

8.  Brittleness. 

4.  Fracture  (irregular  or  shelly). 

5.  Hardness. 

6.  Structure  features  (make  drawing). 

7.  Place  small  fragments  of  soft  coal  in  a  test  tube  fitted  with  a  one-hole  stopper  through  which  is 
pushed  a  short  glass  tube  drawn  to  a  fine  bore.     Heat  the  test  tube  and  light  the  gas  driven  out  through 
the  tube.     Describe  the  various  substances  produced. 


38 


HARD   AND   SOFT   WATER 

Purpose.     To  determine  whether  water  is  hard  or  soft. 

Material.  Three  test  tubes,  strong  soap  water,  distilled  or  rain  water,  limewater,  and  the  water  to 
be  tested. 

1.  Put  distilled  water  into  a  test  tube  (half  full),  add  two  or  three  drops  of  the  soap  water,  and 
shake  vigorously.     What  collects  at  the  top  of  the  water?     How  much  of  it  is  there? 

2.  Repeat  the  operation,  using  limewater  instead  of  distilled  water,  in  another  test  tube.     What 
collects  at  the  top,  and  how  much  is  there  ? 

3.  Again  repeat  the  operation,  using  the  water  to  be  tested,  in  another  test  tube.     What  collects  at 
the  top,  and  how  much  is  there  ? 

4.  Does  the  material  gathered  at  the  top  of  the  test  tube  in  the  last  trial  more  closely  resemble 
that  on  the  distilled  water,  or  that  on  the  limewater  ? 

The  result  will  indicate  whether  the  water  sample  is  soft  or  hard. 

Another  way  to  test  the  relative  amounts  of  mineral  matter  in  samples  of  water  is  to  put  a  drop  of 
each  kind  of  water  upon  a  clean  piece  of  glass.  When  the  drops  have  evaporated,  hold  the  glass  toward 
the  light  and  compare  the  thickness  of  the  deposits. 


39 


STALACTITES   AND    STALAGMITES 

Purpose.     To  show  how  formations  in  caves  are  made. 

Fill  a  large  bottle  with  a  saturated  solution  of  alum  or  photographers'  hypo.  Put  a  siphon  into  the 
bottle  and  by  means  of  a  pinch  cock  or  a  glass  tube  drawn  to  a  fine  point,  cause  the  drops  to  form  very 
slowly  —  one  every  half  minute  —  and  allow  them  to  fall  upon  two  pieces  of  fine-mesh  copper  or  brass 
gauze,  suppoi-ted  one  a  few  inches  below  the  other.  Examine  this  from  time  to  time  and  note  the  growth 
of  the  d.eposits.  Write  below  a  full  description  of  the  experiment  and  make  a  drawing  of  the  apparatus 
and  deposits. 


41 


ALKALI    PLAINS 

Purpose.     To  show  how  arid  plains  become  alkaline. 

Material.     A  dish  of  sand  and  a  saturated  solution  of  alum  or  salt. 

Put  some  dry  sand  into  a  dish  and  wet  it  well,  but  do  not  flood  it,  with  the  alum  or  salt  solution. 
Stand  the  dish  aside  for  a  few  days,  and  a  layer  of  alum  or  salt  will  be  found  over  the  surface.  After 
the  experiment  is  completed,  answer  the  following  questions  :  — 

1.  How  did  the  salt  get  to  the  surface? 

2.  Where  do  the  alkaline  salts  come  from  that  are  found  on  the  alkali  plains? 

3.  How  do  they  get  to  the  surface? 

I 

4.  Why  are  alkali  plains  found  only  where  there  is  little  rainfall? 

5.  How  will  abundant  irrigation  make  these  alkali  plains  productive? 


43 


MODELING 

Sand  Modeling.  Whether  sand  modeling  is  valuable  or  not  iu  representing  very  large  areas,  it 
surely  is  a  great  help  in  the  study  of  tracts  so  small  that  they  can  be  represented  on  a  scale  of  a  mile  or 
two  to  the  inch.  One  particularly  useful  method  of  applying  sand  modeling  is  in  representing  processes. 
A  river  valley  can  be  shown  not  simply  as  a  finished  product,  but  undergoing  the  development  stages. 
And  as  the  pupil  digs  out  the  valley,  or  sees  it  dug  out,  he  does  not  overlook  the  fact  that  there  is  sedi- 
ment to  be  disposed  of.  Processes  like  capture  or  the  lateral  shifting  of  divides,  the  understanding  of 
which  requires  a  clear  conception  of  the  third  dimension,  and  which  are  therefore  so  difficult  to  explain 
by  blackboard  sketches,  are  e'asily  demonstrated  in  the  sand  tray. 

Sand  modeling  is  very  useful,  also,  as  a  test  of  the  pupil's  interpretation  of  a  map.  After  the  pupil 
has  studied  a  map  of  the  Appalachians  or  of  the  Grand  Canyon,  let  him  model  a  portion  of  the  area  five 
or  six  miles  square,  with  very  little  vertical  exaggeration.  The  first  results  will  be  a  revelation  to  the 
teacher. 

The  sand  tray  should  be  of  metal — aluminum,  zinc,  or  galvanized  iron,  16  by  24  inches  or  larger, 
with  sides  not  more  than  two  inches  high.  Common  sand  may  be  used,  but  fine  molding  sand  from  a 
foundry  is  better.  The  sand  must  be  freed  from  lumps  and  the  moisture  evenly  distributed  by  working 
through  the  fingers.  The  beginner  usually  gets  the  sand  too  moist ;  it  should  be  stiff,  just  wet  enough 
to  stick  well  together.  The  method  of  manipulation  is 
very  important.  If  you  try  to  press  down  the  sand  for 
valleys  and  pinch  it  up  or  heap  it  up  for  divides,  you 
can  hardly  get  good  results.  Most  land  surfaces  are 
plains,  high  or  low,  more  or  less  cut  up  by  streams. 
Follow  nature's  method.  Level  off  a  heap  of  well- 
packed  sand,  then  cut  out'the  valleys.  A  simple  little  SAND  MODELING  TOOL 
sand-modeling  tool  will  be  found  of  great  convenience. 

It  has  a  straight  edge  three  or  four  inches  long,  for  shaving  off  a  level  surface,  and  curves  and  angles  for 
cutting  valleys  of  different  forms.  In  cutting  the  valley,  scrape  off  thin  shavings  of  sand  —  a  deep 
stroke  is  likely  to  break  the  sand  mass.  For  volcanic  cones  and  other  forms  not  developed  from  a  plain, 
the  sand  may  be  heaped  up  by  the  fingers. 

A  good  exercise  is  to  model  from  memory,  and  correct  with  the  map  in  hand.  Only  the  most 
general  features  of  a  landscape  should  be  shown,  and  the  work  should  be  rapid.  After  the  first  trial, 
half  a  recitation  period  is  enough  time  for  one  exercise.  Remember  that  sand  is  to  be  used  to  repre- 
sent topography  —  the  character  of  valleys  and  divides.  Simple  position  can  be  shown  with  less  trouble 
on  the  blackboard. 

Permanent  Relief  Models.  If  it  is  desired  to  represent  the  details  of  a  region  accurately  to  scale,  a 
more  durable  model  should  be  made.  By  means  of  carbon  paper,  trace  the  lowest  contour  of  the  map  on 
cardboard ;  cut  the  cardboard  along  the  tracing,  and  glue  the  piece  on  a  board.  On  another  piece  of  card- 
board trace  the  next  higher  contour,  cut  it  out,  and  glue  it  on  the  first  piece.  Great  care  must  be  taken 
to  get  the  new  piece  exactly  in  the  proper  place ;  one  way  to  do  this  is  to  make  pinholes  at  the  points 
of  high  elevation,  through  the  map  and  through  each  piece  of  cardboard  while  the  contour  is  being- 
traced  on  it.  Continue  till  all  the  contours  have  been  traced  and  the  pieces  mounted.  With  molding 
clay  wet  with  glue,  fill  in  the  angles  at  the  edges  of  the  cardboard  so  that  the  surface  shall  slope 
naturally.  Paint  or  shellac  will  make  the  model  complete. 

The  work  may  be  divided  among  the  members  of  a  class,  each  marking  and  cutting  one  contour. 
By  choosing  cardboard  of  a  certain  thickness,  the  vertical  exaggeration  can  be  made  as  desired.  E.g., 
if  the  map  scale  is  one  inch  to  the  mile,  and  the  contour  interval  100  feet,  cardboard  of  a  thickness  50 
sheets  to  the  inch  would  give  no  vertical  exaggeration. 

To  get  duplicates  of  the  model,  first  make  a  plaster  mold ;  then  in  it  you  can  make  as  many  casts 
as  you  wish.  To  make  the  mold,  the  model  must  first  be  well  coated  with  shellac.  When  this  is 
thoroughly  dry,  surround  the  model  with  a  rim  higher  than  its  highest  point.  Cover  the  model  and 
inner  surface  of  the  rim  with  a  light  lubricating  oil  (sperm  is  good  ;  do  not  use  a  drying  oil),  and  pour 
•in  plaster  of  Paris,  wet  to  an  easy-flowing  consistency.  After  twenty  or  thirty  minutes  the  mold  can 
be  removed  from  the  model,  and  any  flaws  touched  up.  After  the  mold  is  dry,  give  its  inner  surface 

45 


two  or  three  coats  of  shellac.  Oil  it  as  you  did  the  model,  and  pour  in  liquid  plaster  for  the  cast.  If 
the  heads  of  two  or  three  small  bolts  are  imbedded  in  the  plaster  while  it  is  setting,  the  cast  can  be 
conveniently  fastened  to  a  board.  Hair  or  some  other  binding  fiber  should  be  mixed  with  the  plaster 
before  wetting,  that  the  cast  may  not  fall  to  pieces  if  it  should  sometime  be  cracked. 

A  Wet  Laboratory.  A  lead-topped  table,  several  feet  long,  having  raised  edges,  and  supplied  with 
running  water,  will  lend  considerable  interest  to  the  study  of  land  forms. 

One  exercise  consists  in  building  up  a  mound  two  or  three  feet  square  of  well-packed  molding 
sand.  Make  the  mound  six  to  ten  inches  high,  with  nearly  vertical  sides  and  level  top.  Over  the  top 
scatter  pieces  of  slate  an  inch  or  two  across,  and  a  few  large  pebbles.  Cover  an  inch  deep  with  sand 
and  pack  down  hard,  hammering  in  some  small  depressions  an  inch  or  two  deep  to  serve  as  lake  basins. 
Turn  a  very  fine  spray  over  the  model  in  such  a  manner  that  one  edge  and  a  small  part  of  the  top  are 
not  affected,  so  as  to  remain  for  comparison.  Build  a  dam  across  the  outlet  of  the  table  so  that  the  run- 
off will  form  a  body  of  water  three  or  more  inches  deep,  in  which  deltas  and  fine  offshore  deposits  will 
form.  Ravines,  head  erosion,  development  and  recession  of  waterfalls  (positions  marked  by  small 
stakes),  disappearance  of  lakes,  and  differential  erosion  can  be  clearly  shown.  Before  drawing  off  the 
large  body  of  water,  fan  it  into  waves,  and  a  clearly  cut  shore-line  will  be  developed. 

After  the  valleys  are  well  formed,  the  effect  of  a  sinking  coast  can  be  well  shown  by  increasing  the 
depth  of  the  body  of  water.  The  effect  of  a  rising  coast,  in  producing  a  coastal  plain  with  flat  divides, 
can  be  shown  by  decreasing  the  depth  of  the  water. 

To  develop  water  gaps  and  monadnocks,  imbed  some  vertical  layers  of  sun-baked  modeling  clay.  A 
mountain  fold  may  be  made  to  rise  across  the  stream  by  imbedding  horizontally  a  short,  narrow  board, 
from  the  ends  of  which  vertical  wires  extend  up  through  the  sand,  so  that  by  lifting  the  board  a  little  at 
a  time  the  overlying  sand  may  be  cautiously  raised  as  the  stream  cuts  across  the  ridge. 

Another  interesting  result  can  be  secured  by  laying  two  or  more  strings  of  tubing  from  the  water 
faucet  along  the  top  of  the  modeling  table,  and  building  over  them  a  plateau  -similar  to  the  one'described 
above.  Do  not  use  the  spray,  but  adjust  the  ends  of  the  tubing  so  that  the  water  will  emerge  as  springs 
on  the  plateau,  and  produce  the  canyon  valleys  characteristic  of  a  rainless  region. 

Some  pupils  may  increase  the  general  interest  by  modeling  a  bit  of  landscape,  such  as  a  valley  con- 
taining a  stream  with  a  waterfall,  and  dotting  the  hillsides  with  toy  trees,  houses,  factory  buildings,  and 
coal  mines,  and  developing  a  system  of  roads  and  railroads  resulting  from  the  topography. 


46 


FIRST  EXERCISE  WITH  CONTOURS 

Purpose.     To  familiarize  pupils  with  the  use  and  meaning  of  contours. 

Material.  A  large  board  or  table,  a  quantity  of  fine,  moist  sand,  some  blocks  of  wood  one  inch  thick, 
and  a  pointer.  (Note.  If  it  is  not  convenient  for  each  pupil  to  make  this  model,  a  few  of  them  under 
the  direction  of  the  teacher  may  make  a  large  one  for  the  whole  class.) 

Directions.  Fashion  the  moist  sand  into  any  desired  hill-form  with  irregular  slopes.  Make  a  river 
valley  on  one  side  and  a  sharp  ridge  somewhere  else.  The  base  of  the  hill  may  be  regarded  as  sea  level, 
and  is  not  represented  by  any  other  contour  than  the  shore  line.  Place  one  of  the  blocks  on  the  board  or 
table  beside  the  imaginary  island,  lay  the  pointer  upon  it,  and  with  the  end  of  the  pointer  touching  the 
sand,  rtfove  the  block  around  the  island.  The  pointer  will  trace  a  circular  contour  line  in  the  sand  one 
inch  above  sea  level.  Add  another  block  and  trace  a  second  contour  one  inch  above  the  former  line. 

Continue  to  add  blocks  and  trace  contours  until  the  top  of  the  island  is  reached. 

Questions  on  the  Model.  1.  How  many  inch  spaces  are  on  the  model  ?  About  how  much  of  another 
space  remains  at  the  top  ? 

2.  If  the  hill  were  sliced  through  where  the  contours  encircle  it,  what  would  be  the  thickness  of  each 
slice  ?    This  thickness  is  called  the  Contour  Interval  and  is  always  the  vertical  distance  between  a  contour 
and  the  one  next  to  it. 

3.  As  the  contour  interval  is  one  inch,  how  high  is  the  island  ?    How  high  would  the  island  be  if 
the  contour  interval  were  ten  feet?    If  20  feet?    If  100  feet  ? 

4.  Look  directly  down  upon  the  island,  as  you  are  supposed  to  do  when  looking  at  any  contour  map. 

(a)  What  is  the  general  shape  of  the  contours  that  represent  a  hilltop? 

(b)  Notice  that  the  contours  are  not  the  same  horizontal  distance  apart  on  all  sides  of  the  island. 
Where  they  appear  very  close  together,  is  the  slope  of  the  hillside  steep  or  gentle?    What  is  the  charac- 
ter of  the  slope  where  they  are  farther  apart  ? 

(c)  Where  the  contours  cross  the  river  valley,  do  they  bend  up  stream  or  down  stream? 

(d)  How  do  the  contours  bend  where  crossing  the  ridge  ? 

5.  Make  a  drawing  of  the  island  as  nearly  the  shape  of  the  base  as  possible  and  about  four  inches 
across.     Draw  lines  representing  the  contours  each  within  others  as  seen  from  above.     Draw  a  line  for 
the  river.     Make  the  sea-level  contour  and  the  fifth  and  tenth  contours  heavier  than  the  others  (this  is  for 
convenience  in  counting)  and  mark  each  line  with  the  proper  height  above  sea  level  if  the  contour  in- 
terval represents  100  feet. 

6.  Make  the  following  statements  read  correctly :  — 

(a)  Hilltops  are  represented  by  straight-line  closed-curve  contours, 
(ft)  Where  crossing  a  river  valley,  the  contours  bend  up  down  stream. 

(c)  Where  the  contours  are  close  together,  the  slope  is  steep  gentle,  aud  where  they  are  far  apart, 
the  slope  is . 


48 


SECOND    EXERCISE   WITH    CONTOURS 
Purpose.     To  construct  a  contour  map  from  numbers  placed  on  a  chart. 


oo  o  o  o ooo 
oo  ooo  oo 

V  O  <M- 


Directions.  The  numbers  on  the  chart  are  altitudes  in  feet,  and  represent  the  position  of  contour 
lines.  These  lines  show  the  relief  of  an  island  in  the  ocean.  Draw  a  curved  line  through  the  dots 
marked  100,  another  through  the  dots  marked  200,  and  so  on.  No  line  should  touch  or  cross  another  one. 

Questions.  1.  What  is  the  general  shape  of  the  island?  If  one  inch  on  the  map  represents  a 
mile,  how  long  is  the  island  from  south  to  north  (line  AB~)  ? 

2.  Which  end  of  the  island,  the  north  or  the  south,  has  the  steeper  slope  ?     How  can  you  tell  ? 

3.  How  many  hilltops  on  the  island?     How  many  miles  apart  are  they?    How  many  feet  above 
the  sea  is  each  ? 

4.  Draw  lines  representing  the  locations  of  two  rivers  on  the  map.         Label  one  river  C  and  the  other 
D.     How  many  miles  long  is  each  river?     How  high  above  sea  level  is  the  source  of  each  river?     How 
many  feet  of  descent  does  each  river  have?     What,  therefore,  is  the  average  descent  or  grade  per  milr 
of  each? 

Profile  along  Line  KB.  Draw  dotted  lines  from  the  points  where  each  contour  crosses  line  AB  to 
that  line  in  the  rulings  on  the  side  of  the  map  which  has  the  same  value  as  the  contour.  Make  the  dotted 
lines  parallel  with  those  already  drawn  as  guides.  Connect  the  ends  of  the  dotted  lines  within  the  rulings, 
and  the  resulting  line  is  the  required  profile,  which  shows  how  the  western  half  of  the  island  would  look 
from  the  side,  if  the  island  were  cut  through  vertically  along  the  line  AB,  and  the  eastern  half  removed. 

50 


ILLINOIS.     LA  SALLE   SHEET 

Purpose.     To  study  the  earlier  stages  of  valley  development. 

Description  of  the  Region.  The  valleys  selected  for  this  study  have  been  cut  in  the  glacial  drift  and 
underlying  rock  of  north-central  Illinois. 

Location  and  Extent.  1.  To  what  geographic  district  does  this  region  belong?  (See  map  of  Geo- 
graphic Districts,  p.  8.)  On  what  scale  of  iriiles  is  the  sheet  drawn  ? 

Relief  and  Drainage.  2.  What  contour  interval  is  used  here  ?  To  what  drainage  system  does  this 
region  belong? 

A.  A  Study  of  a  Small  Gorge  or  Ravine.     Find  the  small  gorge,  south  of  the  Illinois  River,  about  f 
of  a  mile  west  of  the  Vermilion  River. 

3.  Are  the  contours  that  show  this  gorge  close  together  or  well  spread  apart?    Do  the  sides  have  a 
steep  or  a  gentle  slope  ?    Is  the  bottom  of  this  gorge  broad  or  narrow  ?     How  can  you  tell? 

4.  Does  the  gorge  become  deeper  or  shallower  as  one  goes  from  the  mouth  to  the  source?     How 
shown  ?     Does  the  top  of  the  gorge  become  broader  or  narrower  as  one  goes  in  the  same  direction  ? 

5.  Count  the  contours  that  cross  the  bottom  of  the  gorge  and  tell  how  many  feet  higher  the  head 
is  than  the  mouth.     How  long  is  the  gorge  ?     What  is  the  grade  per  milt- '! 

6.  Does  this  gorge  have  any  tributaries?    Does  the  sheet  show  many  or  few  such  gorges  as  this? 

7.  Make  a  sea-level  profile  on  cross-ruled  paper  across  this  gorge  where  the  .~i(>0-foot  contour  crosses 
it,  and  extend  the  profile  to  the  road  on  each  side;  use  the  standard  scale,  i.e.,  with  the  horizontal 
scale  same  as  in  the  topographic  sheet,  and  the  vertical  scale  1  cm.  =  100  feet.     This  standard  scale 
exaggerates  vertical  distances  about  twenty  times  their  true  proportion.     Beginning  on  west  side  where 
the  road  turns,  and  going  east,  use  following  contours:  620,  610,  500,  610,  620,  620,  road. 

B.  A  Study  of  a  Young  River  Valley.     Notice  the  little  Vermilion  River  that  flows  from  the  north 
into  the  Illinois  at  La  Salle. 

8.  Are  the  contours  along  the  river  close  together  or  widely  separated  ?    Does  this  show  steep  or 
gentle  valley  sides?    Is  the  bottom  of  the  valley  broad  or  narrow,  and  how  can  you  tell? 

9.  About  3}  miles  up  this  river  from  its  mouth  the  480-foot  contour  makes  a  loop  across  it.     Find 
this  place  and  give  the  depth  of  the  valley  here  and  the  width  at  the  top. 

10.  The  contours  along  here  cross  the  valley  about  a  mile  apart ;  what  is  the  grade  per  mile?    How 
does  this  grade  compare  with  that  of  the  gorge  just  studied  ? 

11.  Make  a  sea-level  profile  across  this  valley  (crossing  the  river  at  right  angles)  where  the  480-foot 
contour  crosses  it,  using  the  standard  scale.     Put  this  beside  the  gorge  profile  on  same  sea-level  line. 
Beginning  on  the  west  use  the  following  contours :  620,  620,  610,  600,  48,0,  640,  640. 

C.  A  Study  of  a  Broad  Rh->  r  I  '"•''•''//.     The  size  of  the  Illinois  River  valley  is  largely  due  to  the 
great  volume  of  water  that  flowed  out  from  Lake  Chicago,  the  glacial  enlargement  of  Lake  Michigan. 

12.  Are  the  contours  that  represent  the  valley  sides  close  together  or  well  spread  apart?     What, 
therefore,  is  the  character  of  the  slope?     Is  the  bottom  of  the  valley  (the  flood  plain)  wide  or  narrow? 
How  wide  is  the  flood  plain  opposite  La  Salle?    How  do  the  contour  lines  show  that  the  flood  plain  is 
comparatively  level?     Does  the  river  have  a  direct  or  a  meandering  course  along  its  flood  plain?     How 
many  contours  are  represented  as  crossing  the  river  on  this  sheet?    How  does  the  grade  compare  with 
that  of  the  Little  Vermilion  ? 

13.  Find  a  contour  that  best  represents  the  altitude  of  the  flood  plain.     What  is  it?     Find  a  con- 
tour that  best  represents  the  altitude  of  the  top  of  the  bluff  opposite  La  Salle.     What  is  it  ?     How  deep, 
then,  is  the  valley  ? 

14.  Make  a  sea-level  profile  across  the  valley  a  little  east  of  the  mouth  of  the  Vermilion  River,  and 
extend  it  a  half  mile  or  more  on  each  side,  using  standard  scale.     Make  use  of  only  those  contours  that 
show  change  in  slope.     Put  this  profile  beside  the  others. 

15.  Culture.     In  which  of  the  three  valleys  studied  have  wagon  roads  been  constructed?    Railroads? 
Canals?     Why  cannot  these  means  of  transportation  be  as  easily  constructed  in  the  other  vail' 

16.  Advanced  Questions.     State  two  or  three  eharaeteristirs  that  you  have  noted  which  show  that 
the  valley  of  the  Illinois  River  is  farther  developed  than  that  of  the  Little  Vermilion. 

17.  Do  you  find  a  river  on  the  sheet  that  seems  to  represent  a  stage  of  development  between  the 
Illinois  and  the  Little  Vermilion  ?     If  so,  what  is  it  and  why  do  you  so  regard  it? 

52 


DRAINAGE   AREAS 

Purpose.     To  map  and  to  study  the  drainage  of  the  United  States. 

On  a  map  of  the  United  States  showing  the  rivers  (near  end  of  this  book  —  just  before  the  cross- 
section  paper),  draw  lines  to  show  the  principal  drainage  areas  according  to  the  following  suggestions  :  — 

I.  Atlantic  Drainage  (not  including  the  St.  Lawrence).     Begin  at  the  north  boundary  of  Maine  and 
draw  a  line  along  the  divide  that  separates  the  streams  flowing  into  the  ocean  from  those  flowing  into 
the  St.  Lawrence.     In  west-central  New  York,  the  divide  turns  southward,  separating  the  head  waters  of 
the  Ohio  from  the  Susquehauna,  thence  along  the  Appalachian  Mountains,  through   Florida  to  the 
southern  end.     Label  the  area  east  of  the  divide  "Atlantic  Drainage." 

II.  Gulf  Drainage    (not  including  the  Mississippi).     From  the   place  where  the  previous   divide 
enters  Georgia,  draw  a  line  westward  and  then  southward  to  the  Gulf,  which  will  separate  the  Tennessee 
River  from  the  streams  that  flow  into  the  Gulf  east  of  the  Mississippi.     Then  begin  west  of  the  Mis- 
sissippi River  and  draw  a  line  around  all  the  streams  that  flow  into  the  Gulf,  including  the  Rio  Grande. 
Label  these  two  areas  "  Gulf  Drainage." 

III.  Pacific  Drainage  (not  including  the  Columbia  River).    Begin  just  below  mouth  of  the  Columbia 
River;  draw  a  line  southward  along  crest  of  the  Sierra  Nevada,  and  down  to  the  south  boundary  of 
California.     Label. 

IV.  St.  Lawrence  Drainage.     From  place  where  the  Atlantic  Drainage  divide  turns  southward  in 
New  York,  draw  line  westward  south  of  Lake  Erie,  around  end  of  Lake  Michigan,  and  northward 
around  end  of  Lake  Superior.     Label. 

V.  Mississippi  Drainage  Basin.     From  point  where  divide  turns  eastward  around  Lake  Superior 
draw  line  westward  around  head  of  Mississippi  River,  southward  around  the  head  of  the  Red  River  of  the 
North,  north  and  west  around  head  of  the  Missouri  River,  southward  along  crest  of  Rocky  Mountains 
to  line  inclosing  Gulf  Drainage.     Label. 

VI.  Colorado  River  Basin.     From  point  where  the  divide  crosses  meridian  110°  in  Wyoming,  draw  a 
line  close  along  the  western  side  of  Colorado  River  to  the  Gulf  of  California.     Also,  from  point  where 
the  Rio  Grande  divide  passes  into  Mexico,  draw  a  line  westward  to  the  mouth  of  the  Colorado.     Label. 

VII.  Columbia  River  Basin.     Draw  a  line  from  the  Pacific  divide  in  Oregon  to  the  Colorado  River 
divide,  crossing  northeastern  Nevada,  northwestern  Utah,  and  southeastern  Idaho.     Also  another  line 
from  the  northwestern  corner  of  Mississippi  divide  northwestward  to  Cascade  Mountains,  south  along 
these  mountains  to  central  Washington,  then  southwestward  to  the  ocean.     Label. 

VIII.  Great  Basin  Drainage.     In  southern  California  connect  the  Pacific  divide  with  Colorado  River 
divide.     Label. 

IX.  Hudson  Bay  Drainage.     The  region  immediately  north  of  the  St.  Lawrence  and  Mississippi 
river  basins  drains  into  Hudson  Bay.     Label. 

Color  all  bodies  of  water  blue,  and  the  drainage  areas  different  shades  of  red,  orange,  or  yellow. 
Questions.     1.  Which  of  the  drainage  areas  includes  the  largest  part  of  the  Tinted  States?    Which 
the  smallest? 

2.  Which  has  no  outlet  to  the  ocean  ?    Is  the  rainfall  of  this  basin  heavy  or  light? 

3.  Which  area  occupies  the  central  part  of  the  United  States?    Name  four  important  rivers  belong- 
ing to  this  area. 

4.  What  and  where  is  the  divide  that  separates  the  water  flowing  eastward  into  the  Atlantic  and 
the  Gulf  from  that  flowing  westward  into  the  Pacific? 

5.  About  what  fractional  part  of  the  United  States  drains  toward  the  Atlantic  and  the  Gulf,  and 
what  part  toward  the  Pacific  ? 

6.  Why  is  the  St.  Lawrence  basin  better  for  commerce  than  the  Mississippi  River  basin? 

7.  In  what  area  do  you  live,  and  for  what  is  it  especially  valuable  ? 

54 


THE   MISSISSIPPI   RIVER 

Purpose.     To  study  the  alluvial  valley  of   the  Mississippi  River  from  St.  Paul  to  the  Gulf  of 
Mexico. 

Material.     Two  maps,  four  sheets  each,  published  by  the  Mississippi  River  Commission,  St.  Louis. 

(a)  Map  of  the  alluvial  valley  of  the  upper  Mississippi  River. 

(b)  Map  of  the  alluvial  valley  of  the  Mississippi  River  from  the  head  of  St.  Francis  Basin  to 
the  Gulf  of  Mexico. 

Questions.    A.    The  Upper  Valley.     1.   Give  a  common  width  of  the  flood  plain  (tinted  area)  be- 
tween Cairo  and  St.  Paul. 

2.  Most  of  the  upper  valley  is  preglacial.     Give  the  locations  of  the  two  narrow  stretches  which 
the  river  has  cut  since  the  glacial  period.     They  have  a  swift  current  and  rocky  bottom,  the  only 
obstructions  to  navigation  between  St.  Paul  and  the  Gulf. 

3.  Is  the  general  course  of  the  upper  valley  straight,  regularly  curved,  or  irregular? 

4.  Name  two  places  at  which  the  river  meanders  sufficiently  to  erode  the  sides  of  the  valley. 

5.  How  do  the  courses  of  the  small  streams  in  the  flood  plain  compare  with  the  courses  of  the 
same  streams  in  the  upland  ? 

6.  Name  several  cities  located  on  the  flood  plain,  and  several  on  the  bluffs  bordering  the  flood  plain. 
B.    The  Lower  Valley.     7.   Give  the  maximum  and  the  minimum  width  of  the  flood  plain  south  of 

Cairo. 

8.  Give  the   straighWine  distance  from  Cairo  to  the  mouth  of  the  Mississippi  River,  and  also 
the  river  distance  (see  figures  near  the  mouth).     Explain  the  difference. 

9.  Compare  the  number  of  small  streams  in  the  lower  flood  plain  with  the  number  of  those  in 
the  adjoining  uplands,  and  explain  the  difference. 

10.  How  do  the  meanders  and  cut-off  lakes  of  the  small  streams  compare   in  size  with   those 
of  the  Mississippi  River? 

11.  What  becomes  of  the  water  of  the  small  streams  that  rise  near  the  bank  of  the  Mississippi 
between  Memphis  and  Vicksburg,  and  flow  away  from  it?    Does  the  direction  of  their  flow  indicate  that 
the  banks  of  the  Mississippi  in  this  region  are  higher  or  lower  than  the  general  level  of  the  flood  plain  ? 

12.  How  many  miles  wide  is  the  delta  from  North  Pass  to  Southwest  Pass? 

13.  How  many  miles  is  New  Orleans  from  the  mouth  of  the  Mississippi? 

14.  Name  the  cities  that  are  built  on  the  flood  plain  of  the  lower  Mississippi,  and  those  that  are 
on  the  bluffs  overlooking  the  flood  plain.     Why  should  these  cities  be  at  these  particular  places  on  the 
bluffs? 

15.  At  what  distance  from  the  mouth  of  the  Mississippi  does  its  first  distributary  (the  Atchafalaya) 
branch  off? 

16.  Make  a  sketch  map  of  the  lower  delta  ("  goose  foot  "). 


MINNESOTA.    ST.  PAUL  SHEET 

Purpose.     To  study  the  gorge  and  the  terraces  of  the  Mississippi  River  near  St.  Paul. 

Description  of  the  Region.  The  region  represented  by  this  sheet  is  in  eastern  Minnesota.  The 
surface  was  considerably  modified  by  the  ice  and  water  of  the  glacial  period.  Beneath  a  layer  of  glacial 
drift  is  the  durable  Trenton  limestone,  and  below  this  is  the  soft  St.  Peters  sandstone. 

Location  and  Extent.  1.  Between  what  meridians  does  this  region  lie?  Between  what  parallels? 
How  wide  is  the  sheet  in  degrees?  How  long?  To  what  geographic  district  does  it  belong?  (See 
map  of  Geographic  Districts,  p.  8.) 

2.  What  is  the  exact  scale  of  miles?  What  is  the  approximate  equivalent?  How  many  miles 
wide  is  the  region  shown  on  the  sheet  ? 

Relief  and  Drainage.  3.  What  is  the  contour  interval?  To  what  large  drainage  system  does  this 
region  belong? 

A.  The  Gorge  of  the  Mississippi  River  extends  from  Pike  Island  to  the  Falls  of  St.  Anthony, 
just  at  the  edge  of  the  sheet  (the  Falls  are  not  named  on  the  sheet). 

4.  In  what  direction  does  the  river  flow  along  this  part  of  its  course  ?     How  long  is  the  gorge  ? 
How  wide  at  the  top  and  how  deep  is  it  where  the  wagon  road  crosses  near  its  mouth  at  Fort  Snelling  ? 

5.  What  is  the  name  of  the  largest   tributary  to  the   gorge  from  the   west?      What  falls  are 
in  this  stream?    How  far  up  the  stream  have  the  falls  already  receded?    How  high  are  they  as  shown 
by  the  contours  ? 

B.  The  Terraces  were  formed  by  the  river  cutting  into  its  former  flood  plain. 

6.  In  a   general  way  how  does  the  valley    of    the   Mississippi  below  Pike  Island  compare   in 
width  and  depth  with  that  of  the  Minnesota  ?    This  broad  valley  was  made  during  the  glacial  period, 
and  since  that  time  these  rivers  have  been  forming  a  new  flood  plain  within  the  old  one,  leaving  terraces 
in  some  places. 

7.  Find  the  terrace  on  the  north  side  of  the  Mississippi  between  the  mouth  of  the  gorge  and 
St.  Paul.     How  wide  is  this  terrace  near  St.  Paul?    How  high  above  the  newer  flood  plain  is  it?    What 
part  of  this  terrace  at  St.  Paul  is  covered  with  buildings?    Do  you  consider  these  buildings  safe  from 
floods,  and  why?    Are  those  on  the  newer  flood  plain  safe,  and  why? 

Culture.  8.  Can  river  boats  go  very  far  above  St.  Paul?  Why?  Give  a  reason,  then,  for  the 
location  of  St.  Paul. 

Minneapolis,  about  ten  miles  farther  up,  has  extensive  manufacturing  industries.  From  what 
source  can  factories  there  derive  power  ?  Why  are  these  two  cities  so  close  together  ? 

Advanced  Questions.     9.   Give  a  reason  why  factories  are  not  built  around  Minnehaha  Falls. 

10.  Give  as  many  reasons  as  you  can  for  believing  the  portion   of  the  Mississippi  above   Pike 
Island  younger  than  the  portion  below. 

11.  Give  reasons  for  believing  the  valley  of  the  Minnesota  River  as  old  as  that  of  the  Mississippi 
below  their  junction. 

12.  Make  a  sea-level  profile  across  the  Mississippi  from  "  S.  Base  "  on  parallel  44°  55'  southward 
to  Pilot  Knob,  using  standard  scale. 


IOWA-ILLINOIS.     SAVANNA  SHEET 

Purpose.  To  study  a  typical  portion  of  the  Mississippi  valley  and  adjacent  upland  along  the 
middle  course  of  the  river. 

Description  of  the  Region.  This  region  lies  in  about  the  same  latitude  as  Chicago.  Although  it 
was  not  covered  by  the  ice  sheet  of  the  glacial  period,  yet  the  water  from  the  melting  of  the  ice  front 
overflowed  a  large  part  of  this  region  and  deposited  a  thick  layer  of  fine  silt.  The  Mississippi  occupies 
a  broad,  well-defined  valley,  which  is  characteristic  of  the  river  from  St.  Paul  to  near  the  mouth  of  the 
Ohio  River. 

Location  and  Extent.  1.  Where  is  this  region  located  ?  To  what  geographic  district  does  it  be- 
long? 

2.    What  is  the  approximate  scale  of  miles?    How  wide  is  the  region  represented  on  this  sheet? 

Relief  and  Drainage.  3.  What  is  the  contour  interval  ?  Are  the  contours  in  general  straight  or 
crooked  on  the  sheet,  and  does  this  show  smooth  or  rough  slopes  ? 

4.  Notice  the  flood  plain  of  the  Mississippi.     How  can  you  tell  where  the  sides  t>f  the  flood  plain 
are?   How  wide  is  the  flood  plain  at  the  southern  end  of  the  sheet?  at  its  narrowest  place  above  Savan  na'.; 

5.  Do  you  find  many  or  few  contours  on  the  flood  plain,  and  what  kind  of  surface  does  this  show  the 
flood  plain  to  have?     Do  the  contours  follow  closely  along  each  side  of  the  river,  thus  showing  that  the 
river  is  cutting  a  new  valley  in  the  floor  of  the  old  flood  plain  as  it  has  done  at  St.  Paul  ? 

6.  The  river  has  a  braided  channel  here,  and  the  inclosed  sandy  islands  show  that  the  river  has  re- 
ceived more  sediment  than  it  can  immediately  move  along.     Do  you  find  contours  on  any  of  these  is- 
lands.?   AVhat  rise  of  water  above  that  at  time  of  survey  would  cover  them? 

7.  The  altitude  of  the  top  of  the  bluff  is  about  840  feet.     What  is  the  altitude  of  the  flood  plain, 
and  how  deep,  then,  is  the  river  valley  here  ? 

8.  What  two  tributaries  of  the  Mississippi  drain  most  of  the  upland  region  on  the  eastern  side? 
How  have  they  changed  the  former  small  relief  of  this  region?     Do  you  call  the  drainage  of  these  two 
tributary  basins  complete  or  incomplete,  and  why  ? 

9.  With  the  blunt  end  of  your  pencil  follow  the  divide  between  Plum  River  and  Rush  Creek  from 
Savanna  to  the  upper  end  of  the  sheet.     Do  any  streams  cross  it  ?     Do  you  think  this  divide  is  a  narrow 
ridge  or  a  broad  strip,  and  why  do  you  think  so? 

Culture.  10.  Which  of  the  two  towns,  Sabula  or  Savanna,  is  in  n ion •  danger  of  floods,  and  why  ? 
What  railroad  crosses  the  Mississippi  here  ? 

11.  Have  the  wagon  roads  been  laid  out  on  the  rectangular  plan,  and  why?     Do  the  wagon  roads 
as  a  rule  follow  divides  or  stream  valleys  ? 

12.  What  is  the  annual  rainfall  of  this  region  ?     (See  p.  8.)     Is  it  sufficient  to  keep  the  small 
streams  running  the  whole  year  ?     Look  for  intermittent  streams,  shown  by  broken  blue  lines.     Is  the 
rainfall  sufficient  for  general  farming  purposes? 

Advanced  Questions.  13.  Where  is  the  line  that  marks  the  boundary  between  Illinois  and  Iowa,  and 
what  would  naturally  change  it  from  time  to  time? 

14.  What  evidence  do  you  find  to  show  that  the  Mississippi  once  had  its  chanm-l  on  the  east  side 
of  its  flood  plain  below  Savanna  ? 

15.  Make  a  sea-level  profile  across  the  Mississippi  at  a  convenient  place  above  Savanna,  to  the  800- 
foot  contour  on  each  side,  using  standard  scale. 


60 


LOUISIANA.     DONALDSONVILLE    SHEET 

Purpose.    To  study  the  swamp  flood  plain  and  levees  along  the  lower  course  of  the  Mississippi  River. 

Description  of  the  Region.  An  arm  of  the  Gulf  of  Mexico  once  extended  far  north  of  this  region 
somewhat  like  the  Chesapeake  Bay  at  present.  This  arm  or  bay  has  been  nearly  filled  with  river 
sediment,  and  the  mouth  of  the  Mississippi  is  now  more  than  180  miles  below  Donaldsonville.  The  dry 
land  or  natural  levees  on  each  side  of  the  river  have  been  made  by  the  more  rapid  deposits  here  at  the 
time  of  floods.  Close  along  the  river  artificial  banks  have  been  built  on  top  of  the  natural  levees,  thus 
keeping  the  water  within  its  channel  except  at  times  of  unusual  floods,  when  the  levees  are  washed  away 
(see  Nita  Crevasse).  Bayou  Lafourche  at  Donaldsonville  is  one  of  the  principal  delta  distributaries. 

Location  and  Extent.  1.  In  what  part  of  Louisiana  is  this  region  located?  To  what  geographic 
district  does  it  belong  ? 

2.  Give  the  approximate  scale  of  miles.  How  does  the  width  of  this  sheet  compare  with  the  St.  Paul 
sheet  in  degrees  and  in  miles?  Explain  any  difference  you  may  find. 

Relief  and  Drainage  3.  What  is  the  contour  interval,  and  does  this  suggest  a  region  of  little  or 
great  relief?  What  relief  is  indicated,  also,  by  the  small  number  of  contour  lines  and  by  the  extensive 
swamps? 

A.  The  Swamp  Flood  Plain.     4.   What  is  the  altitude  of  the  lowest  contour  on  the  northeastern  side 
of  the  Mississippi  ?     On  the  southwestern  side  ?    Is  a  large  or  a  small  part  of  these  swamps  below  this 
contour  level  ?     Are  the  contours  on  these  swamps  close  together  or  far  apart,  and  what  does  this  show 
as  to  the  slope?    Are  there  many  or  few  streams  in  the  swamps?    Do  you  consider  these  swamps  well 
drained  ? 

B.  The  Levees.    5.   What  is  the  altitude  of  the  lowest  contour  anywhere  on  the  levees?     Is  this  con- 
tour near  the  river  or  near  the  swamp?    What  is  the  value  of  the  highest  contour  on  the  levee,  and 
where  is  it  found  ?     Does  the  levee  slope  toward  or  away  from  the  river  ?     Where  do  you  find  two 
contour  lines  very  close  together  ?    Where,  then,  is  the  slope  the  greatest  ?    Do  the  small  streams  flow 
toward  or  away  from  the  Mississippi  ? 

6.  The  outbreak  at  Nita  Crevasse  occurred  in  1890.  Note  its  location,  and  tell  why  an  outbreak  is 
more  liable  to  occur  there  than  on  the  opposite  side  of  the  river.  Where  did  the  outflowing  water  de- 
posit its  sediment,  and  how  has  this  deposit  affected  the  width  of  the  levee  ? 

Culture.  7.  Only  what  portion  of  this  region  is  suitable  for  farming?  What  is  the  annual  rainfall 
of  this  region?  (See  p.  8.)  Will  this  amount  run  off  quickly  where  the  slope  is  so  gentle?  Of  what 
use,  therefore,  are  the  ditches  (the  straight  blue  lines),  and  where  do  they  carry  the  water? 

8.  Where  are  the  two  main  wagon  roads  located  ?    Why  is  not  the  common  rectangular  plan  of 
roads  followed  here? 

9.  Make  a  sea-level  profile  across  the  levees  and  river  near  the  stations  of  Winchester  and  White- 
hall, beginning  and  ending  with  the  5-foot  contour.      Make   the  river  channel    100  feet   deep   and 
containing  90  feet  of  water.     Use  standard  scale. 

Advanced  Questions.  10.  The  principal  crops  of  this  region  are  sugar,  cotton,  and  rice;  by  what 
two  ways  may  they  be  sent  to  market?  Which  way  is  the  quicker?  Which  way  is  probably  the 
cheaper,  and  why  ? 

11.  Make  a  sketch  of  the  river  from  Donaldsonville  to  College  Point  and  mark  the  position  of  the 
swiftest  part  of  the  current  by  a  broken  line.  At  how  many  places  is  the  river  liable  to  break  through 
its  banks  at  flood  time,  and  why  ?  At  what  bends  do  you  find  evidences  of  crevasses  similar  to  the  Nita 
Crevasse  ? 


62 


MISSISSIPPI    RIVER    SHEET   NO.  14 


NOTE.  These  sheets  are  prepared  by  the  Mississippi  River  Commission,  St.  Louis,  Mo.,  and  deal  with  the  com- 
mercial importance  of  the  river.  Scale :  1  in.  =  1  mi.  If  sheet  No.  14  cannot  be  obtained,  sheet  No.  18  may  be  sub- 
stituted by  making  a  few  changes  in  the  questions. 

Purpose.     To  study  river  conditions  that  attend  flood-plain  meanders. 

Description  of  the  Region.  The  region  represented  on  this  sheet  is  about  midway  between  the 
mouth  of  the  Ohio  and  the  Gulf,  and  fairly  represents  a  large  part  of  the  lower  course  of  the  Mississippi. 
The  banks  of  the  river  consist  of  unconsolidated  sand  and  silt,  which  are  easily  cut  away  by  the  current. 

Questions.     1.   Between  what  two  states  does  this  part  of  the  Mississippi  flow? 

2.  The  numbers  in  the  middle  of  the  stream  are  river  distances  in  miles  below  the  mouth  of  the 
Ohio  at  Cairo,  111.     How  far  below  the   mouth  of  the  Ohio   is   Ashbrook  Point   at  Rowdy  Bend? 
Sunnyside  Landing? 

3.  Find  Jones's  Landing,  and  tell  how  many  miles  a  boat  must  sail  to  go  from  there  to  Sunnyside 
Landing.     How  far  does  a  boat  sail  in  going  from  Jones's  Landing  to  Upper  Leland  Landing,  and  how 
many  miles  would  be  saved  if  the  river  were  cut  through  from  one  to  the  other? 

4.  At  Rowdy  Bend  does  the  current  line  (a  dotted  black  line)  go  on  the  outside  or  the  inside  of  the 
middle  of  the  channel  ?    On  which  side,  then,  is  the  current  the  swifter  ?    On  which  side  is  the  river 
cutting  away  its  bank  ? 

.  5.  On  which  side  of  Rowdy  Bend  has  the  sand  bar  (fine  black  dotted  area)  been  formed  ?  Does 
this  represent  a  cutting  or  a  filling  ?  Does  this  operation  and  that  in  your  answer  to  question  4  tend  to 
increase  or  decrease  the  size  of  the  meander  ? 

6.  Examine  the  other  bends  on  the  sheet  and  tell  how  they  compare  with  Rowdy  Bend  in  (1)  loca- 
tion of  current  line  and  (2)  cutting  and  filling. 

7.  Are  these  changes  in  the  course  of  the  river  of  sufficient  importance  to  navigation  to  make  new 
surveys  necessary?     Why  more  necessary  in  the  Mississippi  than  in  the  Amazon  or  Congo? 

8.  Read  the  note  printed  in  red  on  the  side  of  the  map.     When  was  the  first  survey  for  the  map 
made,  and  how  shown  on  the  map  ?    How  long  afterwards  was  the  river  here  again  surveyed,  and  how 
is  the  position  of  the  new  channel  shown? 

9.  Note  the  location  of  the  red  bank  line  on  the  east  side  of  Georgetown  Bend.     How  wide  a  strip 
of  land  was  cut  away  at  this  bend?    How  long  did  it  take  the  river  to  do  this  cutting?    How  wide  a 
strip  is  yet  to  be  cut  away  before  the  river  will  go  across  the  neck,  thus  forming  a  cut-off?    At  the 
same  rate  as  the  previous  cutting,  when  would  this  cut-off  occur  ? 

10.  At  which  of  the  bends  has  the  outer  bank  of  the  river  been  cut  back  the  farthest?   Ho\v  far? 
What  danger  threatens  the  plantations  located  on  the  outside  of  these  bends?    How  has  Greenville 
been  affected  by  the  meanderings  of  the  river  ? 

11.  Find  the  oxbow  lakes  Chicot  and  Lee.     Tell  how  they  were  formed. 

Advanced  Questions.  12.  Explain  why  no  steamboat  landings  are  on  the  inside  of  the  bend.  M;ik-- 
an  ideal  section  across  the  river  at  Rowdy  Bend,  showing  the  relative  depth  of  water  from  bank  to  bank. 

13.  Do  you  think  another  survey  should  soon  be  made?     Why  ? 

14.  How  would  straightening  the  course  of  the  river  affect  its  velocity,  and  what  effect  would  this 
have  upon  the  prevention  of  floods  and  the  amount  of  work  the  river  could  do  ? 

Make  longitudinal  profiles  of  the  Mississippi  River  and  the  Missouri  River  on  a  horizontal  scale  of 
1  cm.  =  100  mi.,  and  a  vertical  scale  of  1  cm.  =  1000  ft. 

MISSOURI  RIVER 


STATIONS 

DISTANCE   FROM 
Moon 

ALTITUDE 

STATIONS 

DISTANCE  FROM 

M.it  in 

Al.TITrllK 

Mouth       .... 

0  miles 

Ofeet 

Mouth     .... 

0  miles 

395  feet 

Ohio  River 

1100  miles 

270  feet 

Bismarck 

li'in  miles 

1620  feet 

Minnesota  River     . 

IDtO  miles 

690  feet 

Ft.  Benton      . 

'JiiT.I  miles 

2170  feet 

Minneapolis     . 

l!i.V)  miles 

705  feet 

Great  Falls     . 

2100  miles 

3300  feet 

Lake  Itasca 

2300  miles 

14(50  feet 

Three  Forks  . 

2310  miles 

4000  feet 

CALIFORNIA.     CUCAMONGA  SHEET 

Purpose.     To  study  alluvial  cones. 

Description  of  the  Region.     The  region  represented  by  this  sheet  is  in  southern  California  and  shows 
a  portion  of  the  southern  slopes  and  outwashings  of  the  San  Bernardino  Mountains. 

Questions.     1.  What  part  of  the  sheet  shows  the  San  Bernardino  Mountains  ?     The  plain  ? 

2.   Do  the  contours  show  that  the  mountains  have  been  little  or  much  worn  by  streams?     How 
shown  ?    What  do  the  contours  show  to  be  the  general  character  of  the  surface  of  the  plain  ? 


3.  Where  does  the  grade  of  the  streams  that  come  down  from  the  mountains  change  from  steep  to 
gentle  ?    Where,  therefore,  do  they  begin  to  deposit  their  load  of  rock  waste  ? 

What  is  this  deposit  called  ? 

4.  In  what  general  direction  do  the  contours  on  the  plain  extend  ?    Where  they  pass  the  mouth  of 
Deer  and  San  Antonio  canyons,  do  they  loop  or  bend  toward,  or  away  from,  the  mountains? 

What  does  this  indicate  ? 

5.  How  do  the  contours  show  that  these  deposits  are  highest  in  the  middle,  or  cone-shaped? 
Where  are  the  cones  the  broadest?  Where  narrowest? 

6.  What  becomes  of  these  mountain  streams  when  they  reach  the  apex  of  the  cone  ?    Therefore,  of 
what  material  are  the  cones  composed  ? 

What  is  the  probable  origin  of  the  streams  that  begin  between  the  towns  of  Pomona  and  Ontario, 
and  flow  southward  ? 

7.  How  do  the  dry  divided  channels  of  the  streams  across  the  cones  show  the  distribution  of  the 
sediment?    Add  a  sketch  to  your  description. 


8.  Considering  towns,  wagon  roads,  etc.,  how  does  the  population  of  a  strip  close  to  the  base  of  the 
mountains  compare  with  one  a  few  miles  away?    Give  a  reason  for  this. 


66 


ILLINOIS.     OTTAWA    SHEET 

Purpose.     To  study  a  region  of  immature  surface  drainage. 

Description  of  the  Region.  This  region  lies  in  the  north-central  part  of  the  state  along  the  Illinois 
River.  The  ground  moraine  of  the  ice  sheet  was  spread  very  evenly  over  the  surface,  and  the  relief  that 
has  developed  since  the  glacial  period  has  been  largely  due  to  the  work  of  streams. 

Location  and  Extent.  1.  On  which  side  of  the  Illinois  River  is  the  largest  area  that  contains  very 
few  contours  ?  What  direction  is  this  from  the  town  of  Ottawa?  To  what  geographic  district  does  this 
region  belong? 

1  2.  What  is  the  scale  of  miles  of  the  sheet?  How  many  miles  north  from  the  Illinois  River  valley 
does  the  level  prairie  extend  ?  How  far  west  from  the  Fox  River  valley  ?  Then  about  how  many  square 
miles  in  this  immature  drainage  region  ? 

Relief  and  Drainage.  3.  What  is  the  contour  interval,  and  does  this  interval  suggest  little  or  much 
relief?  What  .is  the  meaning  of  the  three  closed-curve  contours  on  this  prairie  V  Judging  from  the  size 
of  the  area  encircled  by  each  of  these  contours,  do  you  think  that  the  higher  parts  of  tin-  prairie  are  very 
conspicuous,  and  why  do  you  think  so?  Do  you  think  that  the  lower  places  between  these  elevations  are 
10  feet  below  the  heavy  contours,  and  why  ? 

4.  The  water  that  drains  off  from  this  prairie  reaches  what  stream  on  the  south  ?    The  east?     The 
north  ?    The  west  ?     What  is  the  difference  in  altitude  between  the  central  part  of  this  prairie  and  the 
Illinois  River?    The  Fox  River  about  2j  miles  above  the  town  of  Dayton?    Buck  Creek  at  a  point 
about  J  mile  above  the  word  "  Buck"?     Pecumsaugan  Creek,  where  it  turns  abruptly  westward? 

5.  Along  which  of  the  above  streams,  those  with  deep  valleys  or  those  with  shallow  ones,  has  the 
margin  of  this  prairie  been  most  roughened  by  ravines  and  gorges?     Along  which  streams  will  the  pro- 
cess of  roughening  the  surface  of  the  prairie  proceed  most  rapidly,  and  why?    As  the  drainage  become- 
more  mature,  how  will  the  relief  of  this  prairie  change  ? 

Culture.  6.  To  what  occupation  is  this  prairie  well  adapted?  Find  the  annual  rainfall  here,  ainl 
tell  whether  it  is  sufficient  for  farming.  Is  the  percentage  of  run-off  here  large  or  small,  and  how  can 
you  tell? 

7.  In  what  directions  do  the  wagon  roads  on  the  prairie  extend?     How  far  can  one  travel  in  a 
north-south  road  without  going  up  hill  or  down  more  than  10  feet?    How  far  on  an  east-west  road?    Do 
you  think  the  roads  here  are  level  or  hilly,  and  why  V 

8.  What  near-by  market  do  the  farmers  have  for  their  surplus  produce?     When  they  have  more 
than  enough  to  supply  this  market,  how  may  they  send  it  farther  ? 

Advanced  Questions.  9.  If  this  prairie  has  immature  drainage,  explain  the  absence  of  lakes  and 
swamps. 

10.  Has  the  region  south  of  the  Illinois  River  valley  a  greater  or  a  less  relief  than  the  prairie  north 
of  the  valley  ?     Give  a  probable  reason. 

11.  In  what  way  does  the  work  of  rivers  affect  the  relief  of  an  elevated  smooth  region  ? 

12.  Make  a  north-south  sea-level  profile  along  the  township  line  on  the  east  side  of  the  townships  of 
Utica  and  Waltham,  beginning  at  the  Illinois  and  Michigan  Canal  and  going  as  far  as  the  cross-sect  inn 
paper  will  permit.     Use  standard  scale. 


68 


PICTURE    SUPPLEMENT  — OTTAWA 

Find  on  the  map  the  location  of  each  of  the  places  shown  in  the  following  pictures. 


A.  Looking  north  across  the  prairie,  from  the  top  of  a  windmill  tower  two  thirds  of  a  mile  west  of 
Dayton.  The  field  showing  obscurely  at  the  right  of  the  barn  roofs  is  asparagus  —  grown  for  the 
Chicago  market ;  beyond  it  is  a  cornfield  with  a  rotting  straw  stack  in  the  middle. 

1.  Describe  the  general  appearance  of  the  surface  of  the  land. 

2.  Why  do  some  farmers  here  need  to  spend  hundreds  of  dollars  in  tile-draining  their  land  ? 

3.  Describe  the  farm  buildings  and  surroundings  at  the  left  of  the  center  of  the  picture. 


B.  Looking  north  from  the  bridge  at  Dayton.  The  Fox  River  and  banks  only  can  be  seen  ;  the 
valley  sides  are  at  the  left  and  the  right,  outside  the  picture.  The  remnants  of  a  dam  appear  some 
distance  up  stream.  On  the  map  observe  the  canal  into  which  the  water  was  turned  by  the  dam. 

4.  What  vegetation  covers  the  banks  of  the  river? 

5.  What  material  composes  the  bed  of  the  stream? 

Does  this  indicate  a  swift  or  a  slow  stream  ? 

6.  As  far  as  you  can  see  up  stream,  does  the  water  seem  smooth  or  rough  ?    Does  this  mean  steep 
or  gentle  slope  ? 

69 


C.   The  east  bank  of  the  Fox  River,  below  Dayton  bridge,  but  showing  just  such  a  bank  as  appears 
at  the  east  of  picture  B,  in  the  distance.     The  rock  is  St.  Peter's  Sandstone. 

7.  Describe  the  results  of  the  water's  work  on  the  rock. 

8.  Does  the  water  seem  to  have  worn  more  at  its  present  low  stage,  or  at  the  flood  stage,  when  it 
rises  as  high  as  the  bushes  ? 


D.    Looking  southwest  from  near  the  top  of  the  east  side  of  the  Fox  valley  one  mile  south  of  Day- 
ton.    The  smoke  and  spires  of  Ottawa  are  visible  in  the  distance. 

9.  What  vegetation  appears  on  the  valley  side  at  the  left  ? 

10.  What  reason  have  you  for  supposing  that  the  fields  west  of  the  river  were  formerly  covered 
with  forest? 


11.   Which  side  of  the  valley  seems  to  have  the  steeper  slope? 

Look  at  the  topographic  map  and  see  if  it  is  so. 

70 


NORTH  DAKOTA -MINNESOTA.  FARGO  SHEET 

Purpose.     To  study  the  characteristics  of  a  newly  made  lake  plain. 

Description  of  the  Region.  The  area  shown  on  this  map  is  a  typical  part  of  the  plain  drained  l>\  1 1  it- 
Red  River  of  the  North.  During  the  glacial  period,  this  area  was  covered  by  the  waters  of  Lake  A-;i*- 
siz  long  enough  to  receive  a  deep  deposit  of  clays  and  sands  brought  into  this  lake  by  the  muddy 
streams  from  the  melting  ice  sheet.  When  the  ice  sheet  disappeared,  the  water  drained  off  into  Hud- 
son Bay,  leaving  the  smoath  floor  of  the  lake  exposed  to  the  action  of  weathering  and  erosion. 

Location  and  Extent.  1.  In  what  states  does  this  region  lie  ?  To  what  geographic  district  does  it 
belong  ?  How  many  square  miles  of  the  region  are  shown  on  the  map  ? 

Relief  and  Drainage.     2.   Do  the  contours  indicate  much  or  little  relief  ? 

3.  State  the  general  altitude  of  the  region  in  the  vicinity  of  Red  River  at  the  northern  and  at  i  In- 
southern  border  of  the  map.     What  is  its  average  slope  per  mile?     In  what  direction  '.' 

4.  Name  the  four  largest  rivers.     What  is  the  general  direction  of  their  flow  ?    Why  ? 


5.  Are  their  channels  straight  or  meandering  ?     Why  ? 

6.  Are  the  stream  valleys  wide  or  narrow  ?     Deep  or  shallow  ? 

7.  Are  the  tributary  valleys  few  or  numerous  ?    Explain  the  meaning  of  the  scallops  in  the  900- 
foot  contour  along  the  Red  River  just  north  of  Fargo. 


8.  Are  the  divides  flat,  or  formed  into  ridges  and  hills?     Why  are  they  in  this  form  at  present? 

9.  What  do  the  number  and  depth  of  stream  valleys,  the  shape  of  the  divides,  and  the  general  re- 
lief of  the  region  show  about  the  length  of  time  weathering  and  erosion  have  been  affecting  this  region  ? 

Culture.     10.    How  thoroughly  has  the  topography  of  this  area  permitted  the  Land  Survey  to  carry 
out  its  rectangular  plan  for  wagon  roads  ? 

11.  What  advantages  does  this  area  offer  for  the  construction  of  railroads? 

12.  What  is  the  annual  rainfall  of  this  region?     What  industry  does  nature  invite  here? 


72 


MARYLAND-VIRGINIA.     WICOMICO    SHEET. 

Purpose.     To  study  a  portion  of  the  Atlantic  Coastal  Plain  near  "  Tidewater  Virginia.  " 
Description  of  the  Region.     This  region  with  its  broad  tidal  rivers  and  immature  drainage  is  char- 
acteristic of  the  country  around  Chesapeake  Bay  and  along  much  of  the  coast  south  of  New  York.     The 
surface  was  formerly  smooth  and  sloped  gently  toward  the  ocean.     Beneath  the  surface  are  many 
layers  of  rock  waste  consisting  of  sand,  gravel,  marl,  fuller's  earth,  etc. 

Location  and  Extent.  1.  Along  what  large  river  is  this  region  situated  ?  To  what  geographic  dis- 
trict does  it  belong  ? 

2.  What  is  the  scale  of  miles?  How  wide  is  the  Wicomico  River  at  Stoddard  Point?  Is  this  an 
average  width  for  the  river? 

Relief  and  Drainage.  3.  Where,  on  the  sheet,  is  the  land  represented  as  near  sea  level  ?  Where  is 
the  highest  land,  and  what  is  its  altitude  ? 

4.  Do  any  contours  cross  the  Wicomico  River  ?     What  does  this  indicate  as  to   its  grade  ? 
Have  the  streams  in  Zekiah  and  Gilbert  swamps  steep  or  gentle  grades,  and  how  can  you  tell  ? 

5.  Note  the  land  (divide)  between  Zekiah  and  Gilbert  swamps.     How  wide  is  it  at  Dentsville  ? 

How  high  above  the  swamps  is  the  crest  of  the  divide  at  this  place  ?  Is  the  crest  higher  or  lower 
toward  the  south  ? 

6.  Are  the  contours  on  this  divide  straight  or  crooked  ?     Does  this  indicate  a  smooth  or  a  rough 
surface  ?    What  has  caused  this  ? 

7.  Is  the  crest  of  the  divide  (where  the  wagon  road  is  located)  as  rough  as  the  slopes  on  either 
side?    Why? 

Culture.     8.     Is  the  rectangular  plan  of  wagon  roads  followed  here  ?    Give  a  reason. 

9.  Does  the  location  of  railroads  show  that  the  valleys  or  the  divides  afford  better  facilities  for 
traffic  ? 

10.  The  wagon  road  northward  from  Pope  Creek  village  (mouth  of  Pope  Creek)  goes  directly  over 
the  divide.     Why  does  not  the  railroad  follow  a  similar  course  ? 

Profile.  11.  A.  Make  a  sea-level  profile  from  Pope  Creek  village  northward  along  the  wagon 
road  to  Bel  Alton,  using  standard  scale.  Mark  with  letter  B  where  bridges  were  probably  built. 

B.  Make  profile  between  same  two  places  along  the  railroad.  Mark  with  a  C  places  where  cuts 
were  probably  made  and  with  an  F  where  fills  were  probably  made. 

Advanced  Questions.     12.     Why  is  the  Wicomico  River  so  wide  in  proportion  to  its  length  ? 

Why  is  there  so  much  marsh  (salt  and  fresh)  in  this  region  ? 

13.  If  this  entire  region  should  sink  a  hundred  feet  below  Its  present  level,  what  would  be  the  effect 
upon  Zekiah  and  Gilbert  swamps  ?  What  present  contour  would  then  mark  the  river's  banks  ? 

How  would  these  rivers  then  compare  with  the  present  condition  of  Wicomico  River  ? 


74 


'    WEST  VIRGINIA.     CHARLESTON    SHEET 

Purpose.    To  study  a  region  of  mature  surface  drainage. 

Description  of  the  Region.  The  region  about  Charleston,  West  Virginia,  is  typical  of  a  broad  strip 
of  laud  lying  along  the  western  side  of  the  Appalachian  Mountains.  The  Kan;i\vha  River  divides  this 
plateau  strip  into  two  sections:  the  section  north  is  called  the  Allegheny  Plateau,  and  that  south,  the 
Cumberland  Plateau.  The  rock  consists  of  nearly  horizontal  layers  of  sedimentary  origin.  Workable 
layers  of  coal  are  found  among  the  layers  of  rock. 

Location  and  Extent.  1.  Give  the  location  of  this  region.  To  what  geographic  district  does  it 
belong  ? 

2.  What  is  the  exact  and  the  approximate  scale  of  the  sheet  ?  What  part  of  a  degree  wide  ?  How 
does  the  area  of  this  sheet  compare  with  that  of  the  sheets  previously  studied? 

Relief  and  Drainage.  3.  AVhat  is  the  contour  interval,  and  what  relief  does  the  use  of  such  an  in- 
terval suggest?  Are  the  contours  crowded  together  or  well  spaced  apart,  and  what  does  this  indicate  as 
to  the  steepness  of  slopes  ?  Are  the  contours  grouped  in  spots  or  evenly  distributed  over  the  sheet  ? 
How,  then,  do  different  localities  compare  in  amount  of  relief  ? 

4.  What  is  the  name  of  the  river  that  occupies  the  largest  valley  on  this  sheet  ?    Which  tributary 
drains  the  largest  area  on  the  sheet  ? 

5.  Is  any  portion  of  this  region  a  mile  square  without  streams  ?    Are  the  divides  broad  or  narrow  ? 
What  do  these  facts  show  concerning  the  drainage  of  this  region  (mature  or  immature)  ? 

6.  The  altitude  of  the  top  of  the  Kanawha  valley  at  Lock  No.  4  is  about  1400  feet.    How  deep  is 
the  valley  here?    At  Lock  No.  7  the  top  of  the  hills  along  the  valley  have  an  altitude  of  about  1000  feet. 
What  is  the  depth  of  the  valley  here  ?    How  wide  is  the  bottom  of  the  valley  (the  flood  plain)  at  Lock 
No.  6? 

7.  How  was  the  broad,  deep  valley  of  the  Kanawha  made  ?    As  the  small  valleys  become  deeper, 
will  the  relief  become  greater  or  less  ? 

8.  Does  the  fact  that  the  Kanawha  River  has  a  broad  flood  plain  indicate  a  steep  or  a  gentle  grade? 
What  is  the  total  descent  of  the  Kanawha  River  between  Locks  Nos.  4  and  7?    The  distance  between 
these  locks  is  about  25  miles ;  what  is  the  grade  per  mile  ? 

Culture.  9.  What  is  the  annual  rainfall  of  West  Virginia?  Give  reasons  why  you  think  this 
region  is,  or  is  not,  good  for  farming.  As  forests  cover  these  rugged  hills,  what  industry  has  probably 
developed  here?  What  mining  industry  is  carried  on  among  the  hills? 

10.  Do  the  wagon  roads  follow  the  rectangular  plan  ?  Give  a  reason  for  the  fact.  Are  the  roads 
in  valleys  or  on  divides  ? 

Advanced  Questions.  11.  Do  you  think  the  percentage  of  run -off  in  this  region  is  small  or  large, 
and  why? 

12.  If  this  region  was  formerly  smooth,  as  the  very  even  height  of  the  hilltops  indicate,  why  is  it 
now  so  rough?  After  the  drainage  of  a  region  has  become  mature,  what  \\ork  may  the  streams  con- 
tinue to  do? 


76 


PICTURE    SUPPLEMENT  —  CHARLESTON 


The  picture  shows  a  part  of  the  Allegheny  Plateau  lying  east  of  the  Charleston  region. 

1.  Does  the  river  here  have  a  straight  or  a  winding  course? 

2.  Are  the  sides  of  the  valley  steep  or  gentle  ? 
Are  they  too  steep  for  trees  to  grow  on  them  ? 

3.  Has  the  valley  a  broad  or  a  narrow  flood  plain  ? 

4.  Are  the  tops  of  the  hills  (the  sky  line)  even  or  uneven? 
How  have  these  hills  been  made  ? 

5.  What  must  have  been  the  condition  of  this  whole  region  before  the  river  cut  its  valley? 

6.  Where  are  the  roads  located  ? 
Why  there? 


78 


KANSAS.     CALDWELL    SHEET 

Purpose.     To  study  a  region  in  the  central  part  of  the  Great  Plains. 

Description  of  the  Region.  The  region  represented  on  this  sheet  typifies  a  broad  strip  of  country, 
somewhat  deficient  in  rainfall,  lying  east  of  the  Rocky  Mountains.  The  softness  of  the  rock  and  the 
climatic  conditions  have  combined  to  bring  the  river  valleys  to  an  advanced  stage  of  development. 

Location  and  Extent.  1.  In  what  part  of  Kansas  is  this  region  located?  To  what  geographic  dis- 
trict does  it  belong  ? 

2.  What  is  the  scale  of  miles  ?  How  does  this  scale  compare  with  a  scale  of  1  to  62,500  ?  How  \\  id.- 
a  strip  of  country  is  shown  on  this  sheet  ? 

Relief  and  Drainage.  3.  What  is  the  contour  interval,  and  does  it  suggest  a  region  of  little,  of  mod- 
erate, or  of  great  relief?  What  relief  is  indicated  by  the  railroads  crossing  the  country  without  regard 
to  hills  and  valleys  ? 

4.  Do  you  find  the  contours  grouped  together  in  spots,  or  are  they  very  evenly  spaced  over  the  sheet, 
and  does  this  indicate  uniform  or  variable  slope?     Do  you   find  many  small  closed-curve  contours? 
Therefore,  are  there  many  hilltops  here? 

5.  Are  the  courses  of  the  larger  streams  on  the  sheet  straight  or  winding?     Do  contours  follow 
closely  along  the  sides  of  the  streams,  or  is  there  considerable  space  between  them  and  the  river?     Does 
this  show  a  narrow  or  a  broad  flood  plain?     Are  the  contours  on  the  slopes  of  the  valley  sides  close 
together,  as  on  the  La  Salle  sheet,  or  are  they  well  spaced?     What  kind  of  slope  does  this  fact  indicate? 
As  you  approach  the  river  is  it  easy  to  determine  where  the  valley  sides  begin?    Then  would  you 
classify  these  valleys  as  "  open  valleys  "  or  as  gorges  ? 

6.  Find  where  the    1200-foot  contour   crosses  the  Chikaskia  River,  also  where  the  next  heavy 
contour  up  stream  crosses  it.     How  many  feet  of  descent  does  the  river  have  between  these  two  points  ? 
Measure  as  accurately  as  possible  the  length  of  the  river  between  these  points  and  determine  the  grade 
per  mile. 

7.  Notice  the  divide  between  Chikaskia  River  and  Bluff  Creek  where   a  branch  of  the  Missouri 
Pacific  Railroad  crosses  it.     What  town  is  located  on  the  orest  of  the  divide  ?     How  high  above  the 
Chikaskia  River  is  the  town? 

8.  Does  the  spacing  of  the  contours  indicate  a  steep  or  a  gentle  slope  from  the  town  to  the  river? 
What  kind  of  slope  is  indicated  by  the  course  of  the  railroad?     Do- the  contours  show  that  the  crest  of 
the  divide  is  sharp  or  rounded?     How  do  the  other  divides  on  the  sheet  compare  with  this  in  general 
shape? 

9.  What   is  the  annual  rainfall  of  this  region  ?    Are  there  many  or  few  intermittent  streams,  and 
what  does  this  indicate  as  to  the  frequency  of  rains  ? 

Culture.  10.  The  small  relief  of  this  region  admits  of  what  plan  of  wagon  roads?  Has  the  relief 
influenced  the  direction  of  the  railroads  ? 

11.  How  many  towns  are  on  this  sheet?  How  many  lines  of  railroad ?  Is  the  sheet  well  covered 
with  wagon  roads?  Do  these  facts  show  that  this  part  of  the  Great  Plains  is  well  populated? 

Advanced  Questions.  12.  Give  the  different  characteristics  of  this  region  that  point  to  an  advanced 
stage  of  development. 

13.  What  change  would  take  place  in  the  relief  of  this  region  if  the  annual  rainfall  should  be 
doubled  ? 

14.  Make  a  sea-level  profile  along  the  Missouri  Pacific  Railroad  from  Freeport  to  Ehvclf;  make 
horizontal  scale  same  as  sheet,  and  vertical  scale  1  cm.  =  200  feet,  which  gives  the  same  vertical  exag- 
geration as  the  standard  scale. 


80 


COLORADO.    LAMAR  SHEET 

Purpose.     To  study  irrigation. 

Description  of  the  Region.  The  region  represented  on  this  sheet  is  in  the  southeastern  part  of 
Colorado,  about  100  miles  east  of  Pueblo.  A  number  of  natural  sinks  occur  here,  probably  caused 
by  water  making  caverns  in  the  easily  dissolved  rock,  such  as  rock  salt,  gypsum,  lime,  etc..  ami  tli.- 
roof  caving  in.  These  sinks  may  be  recognized  by  the  presence  of  shallow  lakes  which  usually  go  dry 
during  the  summer. 

Questions.  1.  What  river  crosses  the  sheet?  Which  way  does  it  flow?  Does  it  have  many 
or  few  tributaries  ? 

Do  you  find  many  streams  on  other  portions  of  the  sheet?  Do  these  small  streams  flow  all 
the  year? 

2.  Find  the  annual  rainfall  of  this  region.     In  what  way  does  this  account  for  the  number  of 
streams  here? 

Does  the  amount  of  rainfall  seem  sufficient  for  crops?    For  raising  cattle  and  sheep? 

3.  Notice  the  irrigation  canals.      Follow  the  course  of  the  Colorado  and   Kansas  Canal.      Why 
was  its  course  made  so  crooked  ? 

At  what  altitude  does  it  leave  the  river?  How  high  above  the  river  is  it  at  the  edge  of  the 
sheet  ?  Does  the  water  in  it  flow  faster  or  slower  than  that  in  the  river  ?  Why  ? 


4.  What  land  can  be  successfully  irrigated  by  this  canal? 

What  land  can  be  successfully  irrigated  by  the  canals  on  the  southern  side  of  the  river? 

5.  Notice  the  Arkansas  Valley  Canal.     As  this  begins  in  the  same  river,  how  does  it  happen  that 
it  is  so  much  higher  up  the  valley  side  than  the  Colorado  and  Kansas  Canal? 

What  two   reservoirs  are   used  for  storing   water  along  this  canal  ?     Why   are    they    needful  Y 


What  land  can  be  successfully  irrigated  by  this  canal? 

6.   What  part  of  this  region  seems  to  be  most  thickly  settled?     What  is  the  probable  reason? 
What  change  in  the  productiveness  of  this  region  is  made  possible  by  irrigation  ? 


82 


ARIZONA.     KAIBAB   SHEET 


Purpose.   To  study  a  high  plateau  region. 

Description  of  the  Region.  This  region  belongs  to  a  series  of  plateaus  west  of  the  Rocky  Mountains. 
These  plateaus  are  vast  blocks  of  uplifted  rock,  of  which  the  Kaibab  Plateau  is  one  of  the  highest. 
The  bed  rock  consists  mainly  of  nearly  horizontal  layers  of  sandstone,  limestone,  and  shale. 

Location  and  Extent.  1.  In  what  part  of  Arizona  is  this  portion  of  the  Grand  Canyon  of  the 
Colorado  River?  To  what  geographic  district  does  it  belong? 

2.  How  wide  and  how  long  is  the  sheet  in  degrees?  What  is  the  scale  of  miles?  How  does 
this  compare  with  a  scale  of  ^sVs?  i«W? 

Relief  and  Drainage.     3.    What  is  the  contour  interval,  and  what  kind  of  relief  does  this  indicate? 

4.  Find  four  plateaus  with  names.     Locate  each  with  respect  to  the  Colorado  River,  and  give  the 
altitude  of  the  highest  heavy  contour  on  each.     Are  the  tops  of  these  plateaus  smooth  or  rough  ? 

5.  What  is  the  altitude  of  the  bottom  of  the  Colorado  Canyon  in  the  central  portion  of  the  sheet 
as  shown  by  the  heavy  contour  close  along  the  river?     How  far  below  the  top  of  Powells  Plateau  is  it  V 

6.  Note  the  two  groups  of  closely  spaced  contours  on  each  side  of  the  Colorado  River  between  Kanab 
and  Cataract  creeks.     The  outer  groups  indicate  the  sides  of  the  old,  or  outer,  valley  and  the  others  the 
new,  or  inner,  valley.     How  high  above  the  river  is  the  top  of  the  inner  valley?     How  high  is  the 
top  of  the  outer  valley  above  the  inner  gorge  ?     What  is  the  total  depth,  then,  of  the  Grand  Canyon 
here?     How  wide  is  the  outer  valley  here? 

7.  What  is  the  annual  rainfall  of  this  region?    Why  are  so  many  gorges  without  water  during  a 
large  part  of  the  summer  ? 

8.  What  soon  becomes  of  the  water  that  issues  from  such  springs  as  Mangum  Spring  and  Big 
Spring?     Why  should  springs  be  so  carefully  mapped  in  a  region  like  this? 

Culture.  9.  Do  you  find  many  wagon  roads,  railroads,  towns,  and  other  signs  of  human  activity  in 
this  region  ?  Give  a  reason  for  this  condition. 

Profile.  10.  Use  the  following  data  to  construct  a  sea-level  profile  across  the  Grand  Canyon  at 
a  place  near  the  mouth  of  Cataract  Creek.  The  horizontal  scale  is  1  in.  =  1  mi. ;  make  the  vertical  scale 
1  cm.  =  2000  ft.  This  gives  a  profile  with  practically  no  vertical  exaggeration.  The  first  line  gives 
distance  from  starting  point  in  centimeters,  and  the  second  line  gives  altitude  of  each  station  in  feet. 
Make  the  river  channel  4  mm.  wide  and  25  ft.  deep. 


CM. 

.0 

1.8 

1.9 

2.6 

2.8 

7.4 

7.6 

8.2 

9.0 

0.4 

9.6 

14.3 

14.4 

14.9 

15.0 

17.0 

ALT. 

6250 

6250 

5750 

5500 

5000 

4000 

3000 

2000 

2000 

3000 

4000 

.-,000 

.v.oo 

5750 

6250 

fL'.-io 

Advanced  Questions.     11.   If  scale  of  miles  is  taken  as  the  indication  of  economic  importance,  how 
does  this  region  compare  with  the  others  you  have  studied  ? 

12.  Explain  why  the  Colorado  River  has  been  able  to  cut  so  deep  a  channel  here. 

13.  Why  are  springs  more  abundant  on  the  side  of  Kaibab  Plateau  than  elsewhere  on  the  sheet? 

14.  On  which  plateau  would  a  ranchman  be  most  likely  to  find  grazing  and  forests  ?    Why? 

15.  Small  tributary  valleys  to  the  Grand  Canyon  are  more  numerous  along  the  front  of  the  Kaibab 
Plateau  than  elsewhere.     Give  a  reason  for  this. 

16.  Make  a  longitudinal  profile  of  the  Colorado-Green  River,  using  the  following  data.     In  the 
horizontal  scale  have  1  cm.  =  100  mi.,  and  in  the  vertical  scale  have  1  cm.  =  2000  ft. 


STATIONS 

DISTANCE  FROM  MOUTH 

ALTITUDE  ABOVE  MOUTH 

Mouth        
Second  Sta  
Third  Sta  

0  miles 
600  miles 
900  miles 

Ofeet 
1000  feet 
3°00  feet 

Fourth  Sta  

1430  miles 

4750  feet 

Fifth  Sta.          .        .    •     
Source        

1650  miles 
1800  miles 

6250  feet 
7800  feet 

84 


PENNSYLVANIA.    HARRISBURG  SHEET 


Purpose.     To  study  a  portion  of  the  Appalachian  Mountains  in  Pennsylvania. 

Description  of  the  Region.  The  region  represented  on  this  sheet  is  typical  of  the  northern  Appa- 
lachian Mountains.  The  ridges  are  the  upturned  edges  of  durable  sandstones  and  conglomerates,  while 
the  valleys  between  them  have  been  made  in  weaker  limestones  and  shales. 

Location  and  Extent.  1.  In  what  part  of  Pennsylvania  is  this  region  located?  To  what  system  of 
mountains  does  it  belong? 

Relief  and  Drainage.  2.  What  is  the  contour  interval?  Are  the  contour  lines  spread  evenly  over 
the  sheet,  or  are  they  grouped,  and  what  does  this  indicate  as  to  the  relief  in  different  places  ? 

3.  Name  the  four  prominent  ridges  shown  on  the  sheet  east  of  the  Susquehanna  River,  and  give  the 
elevation  of  the  highest  heavy  contour  on  each.    About  how  many  miles  apart  are  the  crests  of  the  ridges  ? 

4.  Do  the  contours  on  the  sides  of  the  ridges  run  nearly  straight,  or  ar-e  they  crooked ;  and  does  this 
indicate  smooth  or  rough  slopes?   Do  many  or  few  streams  flow  down  the  sides  of  these  ridges  from  the 
crest,  and  have  they  cut  deep  gorges  ?  Are  the  tops  of  the  ridges  composed  of  sharp  peaks,  or  is  the  crest 
line  nearly  smooth  ?   Draw  a  line  on  your  paper  to  represent  the  crest  line  of  Second  Mountain. 

5.  What  direction  has  the  Susquehanna  River  with  respect  to  the  direction  of  the  ridges  ?     Through 
how  ma'ny  ridges  shown  in  the  figure  below  has  the  river  cut  water  gaps? 

»  6.  How  deep  is  the  water  gap  at  Second 
Mountain?  How  wide  is  the  gap  at  the  top 
(at  1200  foot  contour)  ?  How  wide  at  the 
bottom  ?  Is  the  river  wider  or  narrower  at 
this  gap  than  either  above  or  below  it? 
Give  a  reason  for  this. 

7.  What  direction  do  the  tributaries  of 
the  Susquehanna  River  have  with  respect  to 
the  direction  of  the  ridges?  In  what  kind 
of  rock  are  these  streams  working?  What 
is  the  grade  per  rnile  of  Stony  Creek  from 
Watertank  to  Ellendale  ?  What  is  the  grade 
of  the  Susquehanna  from  the  water  gap 
at  Second  Mountain  to  just  below  Sheets 
bland? 

Culture.  8.  What  is  the  name  of  the 
principal  city  on  the  sheet,  and  what  is  its 
political  relation  to  the  state?  How  high 
above  the  river  are  the  capitol  buildings 
(center  of  city) ? 

9.  Is  the  rectangular  plan  of  wagon 
roads  followed  on  this  sheet?  Give  a 
reason.  How  are  the  railroads  influenced 
by  the  relief?  Name  portions  of  this  region 
that  are  suitable  for  farming. 

Profile.  10.  Make  a  sea-level  profile 
across  the  ridges  from  the  "P"  in  the  nann- 
Powell  Creek  (near  Powell  Valley)  to  the 
"P"  in  Paxton  Creek,  using  only  the  con- 
tours in  the  valleys  and  on  the  crests  of  the 

ridges.     Use  a  vertical  scale  of  1  cm.  =  2000  feet,  which  gives  nearly  true  proportions. 

Advanced  Questions.     11.    Is  the  course  oif  the  Susquehanna  independent  of,  or  dependent  upon,  the 

direction  of  the  ridges?     Give  reason  for  your  answer.     What  must  have  been  the  relief  of  this  region 

when  the  river  first  took  its  present  course  ? 

12.   Why  are  the  crests  of  these  ridges  so  even,  instead  of  being  rough  like  the  Rocky  Mountains  .; 

What  evidences  do  you  find  that  these  ridges  are  being  destroyed?     (See  figure.) 

86 


COLORADO.     ANTHRACITE    SHEET 

Purpose.     To  study  a  portion  of  the  Rocky  Mountains. 

Description  of  the  Region.  The  region  represented  on  this  sheet  contains  no  large  range  of  moun- 
tains, but  is  fairly  typical  of  Rocky  Mountain  topography.  Sedimentary  rock  abounds,  and  the  upturned 
edges  of  the  more  resisting  layers  form  such  peaks  as  Garfield,  Peeler,  and  Mt.  Kmmons.  Outflows  of 
lava  are  plentiful,  and  such  mountains  as  Carbon,  Axtell,  Gothic,  and  Marcellina  are  of  igneous  origin. 
Lava  pouring  up  through  long  fissures  in  the  sedimentary  rock  has  formed  Anthracite  and  Ruby  ranges. 
The  drainage  belongs  to  the  Gunnison-Grand-Colorado  River.  , 

Location  and  Extent.  1.  In  what  part  of  Colorado  is  this  region  located?  To  what  mountain  sys- 
tem does  it  belong? 

2.  What  is  the  scale  of  miles?      How  far  from  the  top  of  Mt.  Carbon  to  the  top  of  Mt.  Axtell? 
From  Mt.  Carbon  to  Mt.  Emmons  ? 

3.  What  does  the  use  of  this  large  scale  indicate  as  to  the  economic  importance   of  this  region  ? 
Give  names  of  places  on  the  sheet  that  point  to  various  mining  activities. 

Relief  and  Drainage.  4.  What  is  the  contour  interval?  Why  is  it  necessary  to  have  a  greater  in- 
terval than  on  the  Harrisburg  sheet?  Give  the  greatest  altitude  of  Anthracite  Range  and  of  Ruby 
Range. 

5.  Do  the  different  ranges  and  ridges  on  this  sfeet -extend  in  the  same  direction?      How  does  the 
arrangement  here  compare  with  the  Appalachian  ridges  on  the  Harrisburg  sheet?      Are  the  crests  of 
the  Ruby  and  Anthracite  ranges  even  or  uneven  ?    Draw  a  line  across  your  paper  that  you  think  repre- 
sents the  crest  of  Ruby  Range,  and  mark  the  positions  of  five  high  peaks.     How  does  this  line  coni]>;ii> 
with  the  crest  line  of  Second  Mountain  in  Pennsylvania? 

6.  As  you  look  over  the  sheet,  does  it  appear  that  the  streams  have  done  little  or  much  work  of 
erosion?     How  can  you  tell?     What  streams  have  cut  deep  gorges  in  parts  of  this  region? 

Profile.  7.  Make  a  sea-level  profile  from  the  top  of  Gothic  Mountain  to  the  top  of  Peeler  Peak, 
using  a  vertical  scale  of  1  cm.  =  2000  ft.,  which  gives  a  profile  with  but  little  vertical  exaggeration.  Name 
the  different  parts  of  the  profile. 

Culture.  8.  How  well  is  the  region  supplied  with  wagon  roads?  Where  have  they  been  located  to 
secure  easy  grades? 

9.   How  many  railroads  have  been  built  here?    What  purpose  do  they  serve ? 

Advanced  Questions.  10.  Notice  the  large  number  of  open  valleys  or  basins  on  the  flanks  of  the 
ranges.  These  at  one  time  contained  glaciers,  and  are  known  as  glacial  cirques.  What  characteristics 
do  they  have  that  lead  you  to  think  they  once  contained  glaciers? 

11.  Some  of  these  basins  are  good  examples  of  hanging  valleys.      One  may  be  seen  just  north  of 
Cascade  Mountain,  containing  three  steps.     Two  of  the  levels  contain  lakes.     What  is  the  difference 
in  their  altitude?     How  high  is  the  lower  lake  above  the  level  next  below  it?     Sketch  a  longitudinal 
profile  of  this  whole  valley,  showing  the  different  steps.  Explain  how  this  valley  may  have  been  formed. 

12.  Locate  other  hanging  valleys. 


88 


CALIFORNIA.  SHASTA  SPECIAL  SHEET 


Purpose.     To  study  a  young,  but  inactive,  volcano. 

Description  of  the  Region.  Mt.  Shasta,  a  typical  young  volcano,  is  near  the  southern  end  of  the 
Cascade  Mountains.  The  secondary  cone,  Shastina,  is  of  more  recent  origin  than  Mt.  Shasta  proper, 
and  still  retains  its  crater  except  on  the  western  side,  where  a  lava  outflow  carried  away  the  rirn. 

Location  and  Extent.  1.  In  what  part  of  California  is  Mt.  Shasta?  To  what  range  of  mountains 
does  it  belong?  Give  as  nearly  as  possible  the,  latitude  and  longitude  of  the  top  of  Mt.  Shasta. 

2.  What  is  the  scale  of  miles?  What  is  the  distance  from  the  top  of  Mt.  Shasta  to  the  top  of 
Shastina?  How  long  is  the  Sisson  Southern  Trail,  leading  from  the  Southern  Pacific  Railroad  to 
the  top  of  Mt.  Shasta  ? 

Relief  and  Drainage.  3.  What  is  the  contour  interval  ?  Does  this  interval  indicate  a  region  of  small 
or  of  great  relief  ?  Of  gentle  or  of  steep  slopes  ?  What  shape  do  the  contours  show  the  volcano  to  have  ? 

4.  How  does  the  closeness  of  the  contours  near  the  top  of  Shasta  compare  with  those  near  the  base, 
and,  therefore,  how  does  the  steepness  of  slope  near  the  top  compare  with  that  near  the  base? 

5.  What  is  the  altitude  of  Mt.  Shasta?     Of  Shastina?     How  many  feet  high  must  one  climb  going 
from  Sisson  to  the  top  of  Mt.  Shasta?    What  is  the  average  grade  per  mile? 

6.  What  two  kinds  of  volcanic  material  have  built  up  the  cone  of  Mt.  Shasta  as  shown  by  the  names 
on  different  parts  of  the  volcano?     Have  the  small  cones  been  roughened  by  stream  action?     Does  this 
fact  show  that  they  are  young  or  old? 

7.  On  which  side  of  Shasta  are  the  streams  most  abundant?     Least  abundant?     Which  of  these 
streams  has  the  largest  valley  ?     How  deep  is  this  gorge  where  the  6000-foot  contour  crosses  the  stream  ? 
Why  do  some  streams,  such  as  Panther  Creek  and  Inconstance  Creek,  have  a  continuous  flow  in  the  upper 
part  of  their  courses  and  then  become  intermittent  or  entirely  lost  farther  down? 

Culture.  8.  Are  there  many  wagon  roads  and  trails  on  Mt.  Shasta?  Why?  Explain  why  the  rail- 
road has  such  a  winding  course. 

Profile.  9.  Mt.  Shasta  is  too  broad  to  permit  a  complete  profile  on  the  scale  of  the  map.  The  fol- 
lowing west-east  approximate  data  are  given  on  a  reduced  scale.  Use  a  vertical  scale  of  1  cm.  =  5000  ft., 
which  gives  a  slope  with  little  exaggeration.  Label  the  two  summits. 


DISTANCE  FROM 
STARTING  POINT, 
IN  CENTIMETERS 

Al.TITn>K. 

IN  FEET 

DISTANCE  FROM 

STARTIM;  POINT, 
IN  CENTIMETERS 

ALTITI-DE, 
IN  FEET 

i 

0 

4,000 

8i 

14,380 

1 

4,300 

9 

12,000 

2 

5,000 

10 

10,000 

3 

5,700 

11 

8,500 

4 

6,400 

12 

7,500  " 

5 

8,000 

13 

6,400 

6 

10,000 

14 

5,500 

7 

12,433 

15 

4,800 

74 

12,000 

17 

4,000 

90 


BOWLDER   CLAY,    OR   TILL 

Purpose.     To  study  the  composition  and  properties  of  the  rock  waste  in  a  glacial  moraine. 
Material.     A  piece  of  unweathered  bowlder  clay,  a  small  test  tube,  a  piece  of  glass,  water,  hydro- 
chloric acid,  a  blotter,  a  hand  magnifier. 

1.  What  is  the  color  of  the  lump  of  dry  clay  ? 

2.  Is  it  firm,  or  does  it  easily  fall  to  pieces? 

3.  What  do  you  see  in  the  lump  besides  the  very  fine  clay  ? 

Put  a  half  teaspoonf ul  of  the  clay  into  a  test  tube  half  full  of  water,  cover  the  end  of  the  test  tube 
with  your  thumb,  invert,  and  shake  gently  until  the  particles  are  thoroughly  separated  and  suspended  in 
the  water.  Stand  the  test  tube  aside  for  a  few  minutes  until  the  suspended  particles  begin  to  settle. 

4.  Does  the  fine  material,  or  the  coarse,  settle  first? 

5.  About  what  fraction  of  the  material  is  very  fine  ? 

To  get  the  fine  clay  and  coarse  grains  of  the  lump  separated  so  that  you  can  see  them  more  easily, 
put  a  lump  the  size  of  a  pea  on  a  piece  of  glass.  On  it  drop  three  or  four  drops  of  water.  Crush  the 
lump  with  your  finger  and  rub  it  up  in  the  water,  adding  a  few  more  drops,  if  necessary,  to  make  a  thin 
mud.  Tilt  the  glass  a  little  and  absorb  in  a  blotter  the  mud  that  runs  off.  Let  a  few  more  drops  of 
water  run  over  the  coarse  grains  till  they  are  clean.  Examine  the  grains  with  a  magnifier. 

6.  What  different  colors  do  you  find  in  the  grains? 

7.  Are  the  grains  regular,  or  irregular,  in  form? 

8.  Which  grains  are  affected  by  hydrochloric  acid  ?     What  kind  of  rock  are  they  ? 

9.  Put  on  the  glass  a  little  of  the  fine  sediment  caught  on  the  blotter  and  test  with  hydrochloric 
acid.     What  mineral  does  the  test  show  to  be  present  in  the  fine  sediment? 

10.  As  the  fine  sediment  spreads  out  in  the  acid,  does  it  seem  uniform  in  composition,  or  like  the 
coarse  grains,  composed  of  pieces  differing  in  color  and  size? 

11.  Do  you  find  in  unweathered  bowlder  clay  remnants  of  decayed  plants  and  animals  —  as  in  soil  ? 
Give  a  reason. 

12.  What  facts  that  you  have  observed  indicate  that  the  glacial  clay  was  produced  by  the  glaciers 
grinding  firm  rock  to  powder,  and  not  by  the  atmospheric  disintegration  of  rock  ? 


91 


COMPARATIVE    STUDY  OF    GLACIAL   AND    LAKE    (RIVER)    PEBBLES 

N'OTE.     Nearly  all  lake  and  river  pebbles  within  the  glaciated  region  have  been  washed  from  the  drift. 

1.  Does  the  glacial  pebble  have  sharp  angles,  or  are  the  angles  rounded  and  obscure  ?    How  does  the 
lake  (river)  pebble  compare  with  it  in  .this  respect? 

2.  Is  the  general  surface  of  the  glacial  pebble  smooth  or  rough  ?     How  does  the  surface  of  the 
lake  (river)  pebble  compare  with  it  in  smoothness  ? 

3.  Does  the  glacial  pebble  show  any  markings  not  found  on  the  lake  (river)  pebbles?     If  so,  tell 
what  they  are. 

4.  Describe  the  scratches  or  striae  on  the  glacial  pebble  as  regards  (a)  number  (large  or  small) 
(A)  depth,  (c)  uniformity  of  direction. 

5.  Do  you  find  sets  of  striae  running  at  different  angles  ?     If  so,  give  a  possible  explanation. 


6.  If  the  lake  (river)  pebble  was  once  covered  with  striae,  how  may  they  have  been  destroyed? 

7.  How  have  the  striae  on  the  glacial  pebble  been  protected  from  wear  ever  since  they  were  made 
by  the  glaciers  ? 


93 


CALIFORNIA.     SHASTA   SPECIAL   SHEET 

Purpose.     To  study  the  glaciers  on  Mt.  Shasta. 

Description  of  the  Region.  The  snow-crowned  peak  of  Mt.  Shasta  is  very  conspicuous  in  the  scenery 
of  northern  California.  The  top,  which  reaches  about  4000  feet  above  the  timber  line,  is  surrounded 
by  several  small  glaciers. 

Questions.  1.  What  is  the  altitude  of  Mt.  Shasta?  Do  you  think  that  the  precipitation  at  this 
altitude  is  rain,  or  is  it  snow  ?  Why  do  you  think  so  ?  Why,  then,  are  glaciers  found  near  the  top  ? 


2.   How  many  glaciers  are  located  here?    Give  name,  location,  and  length  of  the  longest;  of  the 
shortest. 


3.    As  strong  southwest  winds  prevail  here,  where  does  most  of  the  snow  come  to  rest,  and  where  do 
you  find  the  largest  glaciers  ?     Give  another  reason  for  the  location  of  the  glaciers. 


4.    At  about  what  altitude  do  the  glaciers  on  the  northern  side  melt  ?     Those  on  the  southern  side  ? 
Why  the  difference  ? 


5.  What  different  moraines  are  made  by  these  glaciers? 

6.  Name  two  glaciers  that  occupy  well-formed  valleys.     What  one  spreads  very  broadly  over  the 
side  of  the  mountain  ? 

From  the  presence  of  moraines  and  high  cliffs  among  the  glaciers,  what  do  you  think  the  glaciers 
are  doing  to  the  mountains? 

Advanced  Questions.     7.   What  are  the  sources  of  the  water  that  forms  many  of  the  streams  on  Mt. 
Shasta  ?     Some  of  the  stream  beds  are  lined  with  pebbles,  and  others  not.     Why  the  difference  ? 


8.   It  is  evident  that  snow  falls  on  Shastina.     Why  does  it  not  form  into  glaciers? 


95 


WISCONSIN.     WHITEWATER   SHEET 

Purpose.     To  study  a  glacial  region. 

Description  of  the  Region.  During  the  last  glacial  invasion  one  lobe  of  the  ice  sheet  came  southward 
by  way  of  Green  Bay  and  Lake  Oshkosh,  and  another  by  way  of  Lake  Michigan.  In  southeastern  Wis- 
consin these  two  lobes  met  and  formed  a  kettle  terminal  moraine.  A  small  part  of  this  moraine  extends 
in  a  northeast  to  southwest  direction  across  the  southern  side  of  this  sheet.  The  swampy  area  north  of 
this  moraine  contains  a  number  of  drumlins  that  were  formed  underneath  the  Green  Bay  lobe. 

Location  and  Extent.   1.  Where  is  this  region  located  ?    To  .what  geographic  district  does  it  belong? 

2.   What  is  the  scale  of  miles?    What  is  the  distance  by  railroad  from  Whitewater  to  Palmyra? 

By  wagon  road  from  Palmyra  to  Oak  Hill  ? 

Relief  and  Drainage.     3.   What  is  the  contour  interval?     Where  is  the  relief  greatest?     Least? 

A.  The  Terminal  Moraine.  4.  In  what  part  of  the  sheet  is  the  terminal  moraine  located  ?    In  what 
direction  does  it  extend?    How  was  it  formed? 

5.  What  is  the  altitude  of  the  swamp  in  the  central  part  of  the  sheet  just  north  of  the  moraine? 
The  altitude  of  the  moraine  is  about  1000  feet;  how  much  higher  than  the  swamp  is  it? 

6.  Is  the  surface  of  the  moraine  rough  or  smooth  ?     How  can  you  tell  ? 

The  "  kettles  "  are  shown  by  depression  contours.  Are  there  few  or  many  kettle  holes  ?  Give  the 
depths  of  two  or  three  of  the  deepest.  Do  they  have  any  particular  shape?  (See  picture  of  a  kettle 
hole,  p.  99.) 

7.  Is  the  drainage  of  the  moraine  mature  or  immature?     Give  a  reason  for  this  condition. 

B.  The  Drumlin  Area,    8.    About  what  fractional  part  of  the  region  north  of  the  moraine  is  swainp 
and  what  part  hills  ?     Are  there  many  or  few  drumlins  here  ?     Under  what  glacial  lobe  were  they  formed  ? 

9.  What  general  shape  have  these  drumlins?  Which  way  do  the  long  axes  extend?  Which  way, 
therefore,  did  the  glacier  move? 

Culture.    10.   Mention  some  reasons  for  believing  that  the  dry  land  of  this  region  is  well  settled. 

11.  Which  of  the  lakes  in  this  region  do  you  think  make  good  summer  resorts?  Which  do  not? 
Give  your  reasons. 


Advanced  Questions.   12.   Tell  why  you  think  this  whole  region  has  immature  drainage. 


13.   As  drainage  matures,  how  will  the  farm  land  increase  in  quantity?    How  will  it  improve  in 
quality?     Why? 


97 


PICTURE    SUPPLEMENT  —  WHITEWATER 


This  picture  represents  a  kettle  hole,  such  as  those  shown  on  the  moraine  in  the  southeastern  part 
of  the  Whitewater  sheet. 


This  picture  represents  a  drumlin  such  as  those  on  the  Whitewater  sheet. 

1.  Has  this  drumlin  steep,  or  gentle,  slopes? 

2.  Does  the  drumlin  appear  much  worn  by  water  ? 

3.  What  does  this  i'act  show  concerning  its  age  ? 


99 


NEW   YORK.     WATKINS    SHEET 

Purpose.     To  study  a  glacial  lake  and  its  immediate  surroundings. 

Description  of  the  Region.  The  long,  narrow  lakes  in  western  New  York,  called  Finger  Lakes  from 
their  resemblance  to  the  ringers  of  the  hand,  were  made  by  the  deepening  and  widening  of  river  valleys 
by  glacial  lobes  moving  southward  from  Lake  Ontario.  All  these  lakes  have  a  common  outlet  through 
the  Oswego  River  into  Lake  Ontario. 

Questions.  1.  What  is  the  average  width  of  the  part  of  Seneca  Lake  shown  on  the  sheet? 
What  is  its  altitude  ? 

2.  What  do  the  contours  show  as  to  the  steepness  of  the  shore  on  both  sides  of  the  lake?    How 
high  above  the  lake  is  the  shore  at  a  distance  of  about  \  mile  from  the  lake  ? 

3.  Look  at  several  of  the  small  streams  that  flow  into  the  lake.     In  what  part  of  their  course  is 
the  grade  the  steepest  ? 

The  valleys  of  these  streams  are  examples  of  hanging  valleys.  Sketch  a  longitudinal  profile  of 
the  creek  flowing  through  Reading  Center  on  the  west  side  of  the  lake. 


4.  Does  Watkins  Glen  Creek  flow  through  a  hanging  valley  ?     How  can  you  tell  ? 
How  deep  is  the  glen  where  the  railroad  crosses  it? 

(Pictures  of  the  glen  are  common  and  show  how  the  stream  is  cutting  rapidly  into  the  soft  shale 
and  sandstone  of  the  region.) 

5.  What  becomes  of  the  sediment  brought  into  the  lake  by  all  these  streams?     How  will   the 
width  and  depth  of  the  lake  be  affected  by  it  ?    How  many  miles  of  the  old  lake  bed  at  the  southern 
end  have  become  dry  land  ? 

6.  What  is  the  origin  of  the  many  points  along  the  shore  ?     Why  are  the  largest  points  at  the 
mouths  of  the  largest  streams  ? 

7.  What  appears  to  be  the  future  of  Seneca  Lake  ?     Why  do  you  think  so? 

8.  Make  a  sea-level  profile  across  the  lake  near  the  "a"  in  Seneca,  extending  it  2  or  3  miles  back 
on  to  the  upland  at   each    side.     Use  a  vertical    scale  of    1    cm.  =  200    ft.     What    is    the   vertical 
exaggeration  ? 


101 


NEW   YORK.     NIAGARA   SHEET,    OR   NIAGARA   FALLS   AND   VICINITY 


Purpose.     To  study  Niagara  River  and  Falls. 

Description  of  the  Region.  The  region  represented  on  this  sheet  lies  between  Lake  Erie  on  the  south 
and  Lake  Ontario  on  the  north.  The  land  consists  mostly  of  two  plains  :  (1)  The  lower  plain  extends 
from  Lake  Ontario  south  to  Lewiston,  where  a  line  of  bluffs  runs  nearly  parallel  with  the  lake;  this 
bluff,  or  escarpment,  was  the  shore  of  Lake  Iroquois,  the  glacial  enlargement  of  Lake  Ontario.  (2)  The 
upper  plain  extends  from  this  escarpment  southward  beyond  the  limits  of  the  sheet.  On  the  lower  plain 
underneath  a  layer  of  lake  silt  is  a  thick  layer  of  shale,  and  on  the  upper  plain  underneath  the  glacial 
drift  is  first  a  layer  of  limestone  and  then  the  soft  shale  that  forms  the  bed  rock  of  the  lower  plain. 

The  Whirlpool  is  thought  to  have  resulted  from  the  Falls  cuttirig  into  an  old  valley  that  had  been 
filled  with  glacial  drift. 

A  very  complete  history  of  the  Falls,  together  with  many  excellent  maps  and  photographs,  is  given 
in  Bulletin  45  on  "  Niagara  Falls  and  Vicinity,  "  published  by  New  York  State  Museum,  Albany,  N.Y. 

Location  and  Extent.  1.  Locate  Niagara  Falls  with  reference  to  New  York  state  and  the  Great 
Lakes. 

2.  What  is  the  scale  of  miles  ?  What  is  the  distance  between  the  Falls  and  the  Whirlpool  V  Between 
the  Whirlpool  and  the  foot  of  the  gorge  at  Lewiston  ?  How  long,  then,  is  the  gorge? 

Relief  and  Drainage.  3.  What  is  the  contour  interval  ?  Give  in  the  form  of  a  table  the  altitudes 
of  the  following  places :  Lake  Ontario,  foot  of  the  gorge  at  Lewiston,  the  Whirlpool,  the  foot  of  the 
Falls,  the  crest  of  the  Falls. 

4.  How  many  contours  cross  the  river  on  this  sheet  above  Goat  Island,  and  what  do  they  show  about 
the  grade  of  this  part  of  the  river  ?     What  is  the  average  grade  per  mile  of  the  river  from  the  head  of 
Goat  Island  to  foot  of  Falls  ?    From  foot  of  Falls  to  mouth  of  gorge?   From  Lewiston  to  Lake  Ontario  ? 
Which  one  of  these  four  parts  of  the  Niagara  River  has  the  steepest  grade  ? 

5.  Has  the  river  above  the  Falls  a  deep  or  a  shallow  valley,  and  how  shown  ?     About  how  deep  is  the 
gorge  near  the  foot  of  the  Falls  ?    Near  the  Whirlpool  ?    How  does  the  depth  of  the  valley  change  from 
Lewiston  to  the  Lake  ? 

6.  The  Falls  are  now  retreating  at  the  average  rate  of  4£  feet  per  year.     If  this  rate  has  been  con- 
stant, how  long  has  it  taken  the  Falls  to 

wear  back  from  the  edge  of  the  escarpment 
at  Lewiston  ?  At  the  same  rate  of  retreat, 
how  long  before  the  Falls  will  be  at  the 
upper  end  of  Goat  Island  and  so  combine 
the  two  parts? 

Culture.  7.  Notice  the  canal  that  begins 
about  a  mile  above  the  Falls  and  runs  through 
the  village  of  Niagara  Falls.  Tell  what  you 
can  about  the  use  of  this  and  other  similar 
canals  on  the  Canadian  side.  Why  are  towns 
located  around  the  Falls  ? 

Advanced  Questions.  8.  What  condition 
of  rock  structure  makes  the  sides  of  the  gorge 
so  steep  ?  (See  figure.)  If  the  Falls  began 
at  Lewiston  near  the  close  of  the  glacial 
period,  how  long  ago  did  that  period  end  ? 

9.  Make  a  sea-level  profile  beginning  at 
the  southwest  corner  of  the  Indian  Reserva- 
tion   and   going   north   4  or   5   miles ;    for 
Niagara   Falls   and  Vicinity,    use   standard 

scale;  for  Niagara  sheet  use  vertical  scale  of  1  cm.  =  200  ft.  Another  profile  may  be  made  from  San- 
born  to  Ransoinville  to  show  the  terraces  due  to  the  presence  of  thin  layers  of  sandstone  and  limestone 
within  the  shale. 

10.  Beginning  at  the  same  point  on  the  cross-section  paper,  make  one  profile  of  the  river  from  the 

103 


head  of  Goat  Island  to  Lewiston,  and  another  of  the  bank  along  the  river  between  the  two  places.     The 
difference  between  the  profiles  shows  the  amount  of  cutting  that  has  been  done  by  the  Falls. 

11.  From  the  following  data,  make  a  longitudinal  profile  of  the  St.  Lawrence  River,  using  a  hori- 
zontal scale  of  lcm.=  100  miles,  and  a  vertical  scale  of  1  cm.  =  1000  ft.  What  will  be  the  vertical 
exaggeration  ? 


STATIONS 

DIST.  FROM  MOUTH 

ALT.  ABOVK  Mor  i  n 

DEPTH  OF  LAKES 

Mouth       

0  miles 

0  feet 

Three  Rivers     

500  miles 

0  feet 

Foot  Lake  Ontario   . 

745  miles 

247  feet 

Mouth  Xiagara  River   

930  miles 

247  feet 

1  740  feet 

Foot  Lake  Erie     

960  miles 

573  feet 

Head  Lake  Erie    

1205  miles 

573  feet 

{  210  feet 

Foot  Lake  Huron      

1305  miles 

580  feet 

Head  Lake  Huron     

1568  miles 

580  feet 

I  700  feet 

Foot  Lake  Superior  

1588  miles 

600  feet 

Head  Lake  Superior      

2000  miles 

600  feet 

{1000  feet 

Source  St.  Louis  River      

2100  miles 

1400  feet 

104 


THE    CHICAGO   DISTRICT 

Purpose.     To  study  the  geography  and  the  geology  of  the  Chicago  District. 

Material.     The  Chicago  Folio,  No.  81,  and  the  model  of  Chicago  and  vicinity  by  Siebenthal. 

NOTE.     The  twelve  maps  in  the  folio  are  supposed  to  be  numbered  consecutively  from  1  to  12,  and  reference 
will  be  made  to  them  in  this  way. 

1.  The  Chicago  District.    Make  a  sketch  map  showing  the  location  of  the  district  with  reference 
to  Lake  Michigan  (see  front  outside  cover). 

II.  The  Chicago  Plain  (see  p.  1,  col.  1).     1.   Give  its  location  and  shape. 

2.  La  Grange  (Fig.  1  and  map  1),  Homewood,  and  Gleuwood  (Fig.  1  and  map  4)  are  on  the  outer 
edge  of  this  plain.     How  many  miles  wide  is  the  plain  at  each  of  these  places  ? 

3.  Is  the  plain  fairly  level,  or  hilly  ?     (Maps  1  and  4.) 

4.  What  is  the  approximate  altitude  of  the  plain  ?    (See  heavy  contour  maps  1  and  4.)     How  high 
is  the  plain  above  Lake  Michigan?     (See  figure  in  brown  on  the  lake.) 

5.  To  what  two  causes  is  its  flatness  mainly  due  ?     (P.  6,  col.  2.) 

6.  What  superficial  rock  covers  most  of  the  plain?     (Pgd.  maps  6  and  8  and  legend  on  side  of 
maps.) 

7.  What  material  forms  the  lake  ward  side  of  the  plain?     (Ps.  maps  6  and  8.)  . 

8.  What  sedimentary  rock  outcrops  in  places  over  this  plain?     (Sn.  maps  6  and  8.) 

9.  Among  the  most  prominent  elevations  on  the  plain  are  Rose  Hill  (see  top  of  map  6),  Blue 
Island  Ridge,  and  Stony  Island  Ridge  (see  top  of  map  8).     Of  what  is  each  composed? 

III.  The  Drainage  of  the  Plain.     10.    What  river  drains  the  northern  and  central  parts  of  the  plain? 
What  river  drains  the  southern  part?     What,  the  northwestern?  (See  p.  1,  cols.  3  and  4,  and  maps  1, 
2,  and  4.)     Into  what  larger  body  of  water  does  each  river  flow? 

11.  Do  the  lakes  and  marshes  (maps  3  and  4)  indicate  a  well-drained  or  a  poorly  drained  plain? 
What  is  the  stage  of  erosion  ? 

12.  Give  the  course  and  use  of  the  Sanitary  and  Ship  Canal  —  Drainage  Canal  (p.  1,  col.  3,  maps 
1,2,  and  3). 

IV.  The  Valparaiso  Moraine.     13.   Where  is  the  Valparaiso  moraine  located?     (Fig.  1.) 

14.  Find  its  highest  altitude  four  miles  south  of  Lemont  (map  3).     How  high  above  Lake  Michigan 
is  it  here  ? 

15.  Locate  each  center  from  which  ice  sheets  moved  outward  during  the  glacial  period,  and  name 
each  sheet  (Fig.  6.) 

16.  Notice  the  striae  marked  by  arrows  on  the  limestone  outcrops  (maps  5,  6,  and  8).     In  what  di- 
rection do  they  show  the  glacier  was  moving  ? 

V.  Lake  Chicago.     17.   How  was  Lake  Chicago  produced?     (P.  7,  col.  2.) 

18.  Where  was  its  outlet  ?     (Fig.  7  and  map  3.) 

19.  What  was  the  shape  of  the  outlet  ?     (P.  7,  col.  2,  and  map  3.) 

20.  Was  the  outlet  cut  down  through  the  moraine  and  into  the  bed  rock?     (Map  7.) 

21.  How  wide  at  the  bottom,  and  how  deep  is  the  outlet  at  Lemont?    (Map  3.) 

VI.  Stages  and  Beaches  of  Lake  Chicago.     22.   Find  Glenwood  on  map  8.     What  narrow  deposit  ex- 
tending northwest  and  southeast  (Pb.)  occurs   here  ?     This  line  marks   the    Glenwood   Stage  of   Lake 
Chicago,  and  roughly  follows  the  640-foot  contour.     Turn  to  Fig.  7  and  notice  this  former  lake  margin. 
Name  the  villages  now  located  along  it.     How  high  above  the  present  Lake  Michigan  was  Lake  Chicago 
at  this  stage? 

23.  The  Calumet  Stage  (named  from  the  river)  is  marked -by  a  broken  blue  line  passing  through 
South  Harvey  and  Oak  Glen.     What  deposit  (Pb.,  map  8)  lies  along  it?    Turn  to  Fig.  11,  and  name 
the  villages  now  located  along  this  ancient  beach  line. 

24.  The  Tolleston  Stage  (named  after  Tolleston,  Ind.)  is  also  represented  on  map  8  by  a  broken 
blue  line  running  from  near  Hammond  to  near  Blue  Island.     Notice  the  heavy  contour  along  this  line, 
and  give  its  height  above  Lake  Michigan.     Turning  to  Fig.  12,  name  the  villages  located  along  this 
ancient  beach. 

25.  Copy  the  map,  Fig.  7,  and  add  the  Calumet  and  Tolleston  beach  lines,  Figs.  11  and  12.     Color 

105 


the  present  area  of  Lake  Michigan  blue,  the  three  stages  of  Lake  Chicago  three  shades  of  green,  and  the 
unsubmerged  area  brown. 

VII.  Name  the  economic  products  of  the  district  (pp.  12  and  13)t> 

VIII.  Vertical  Rock  Section.      The  data  for  the  vertical  section  have  been  generalized  from  a  num- 
ber of  deep  wells  in  the  vicinity  of  Chicago.      Use  paper  3  cm.  wide  arid  make  the  vertical   scale 
1  cm.  =  200  ft.     Separate  the  layers  of   sedimentary  rocks  by  lines  across   the  section  at  the   proper 
depth,  but  leave  the  lower  end  open,  as  the  crystalline  rock  extends  to  great  depth.     The  different  for- 
mations may  be  colored  or  filled  with  the  conventional  design  (see  inside  back  cover  of  a  Geological 
Folio). 


NAME  OF  FORMATION 


THICKNESS 


Glacial  Drift 
Niagara  Limestone 
Cincinnati  Shale   . 
Trenton  Limestone 
St.  Peter's  Sandstone 
Magnesian  Limestone 
Potsdam  Sandstone 
Crystalline  Rock    . 


80  feet 

320  feet 

200  feet 

320  feet 

340  feet 

300  feet 
1100  feet 
unknown  depth 


Draw  lines  down  this  section  representing  the  depth  of  the  following  wells  :  — 

Lincoln  Park 1200  feet  deep 

Oak  Park 2200  feet  deep 

Lehman  Well 2600  feet  deep 

IX.  Horizontal  Rock  Section.  The  sedimentary  formations  beneath  Chicago  come  to  the  surface 
(outcrop)  between  Chicago  and  Grand  Rapids,  Wis.  The  data  for  this  northward  horizontal  section 
have  also  been  generalized  in  order  to  make  the  section  as  simple  as  possible.  In  the  horizontal  scale, 
let  1  cm.  =  10  mi.  and  in  the  vertical  scale  1  crn.  =  500  ft.  First  draw  a  sea-level  line  on  the  cross- 
section  paper,  then  lay  off  the  scales.  Locate  dots  for  Chicago  (altitude  600  feet)  and  for  Grand 
Rapids  220  miles  northward,  where  the  crystalline  rock  outcrops  (altitude  1000  feet),  and  connect  these 
dots  with  a  line.  Along  this  surface  line  locate  dots  for  the  outcrops  of  each  formation,  and  beneath 
Chicago  locate  dots  for  their  altitude.  Connect  the  corresponding  dots,  and  label  or  color  the  different 
formations. 


NAME  OF  FORMATION 

ALTITUDE  OF  UNDER  SIPK  <>K 
FORMATION  AT  CHICAGO 

DISTANCE  FROM  CHICAGO  <>K 
UNDER  SIDE  OF  OUTCROP 

Niagara  Limestone  
Cincinnati  Shale       

200  feet 
Ofeet 

70  miles 
85  miles 

Trenton  Limestone           .... 

—  320  feet 

105  miles 

St.  Peter's  Sandstone        .... 

—  660  feet 

1±>  miles 

Magnesian  Limestone       .... 
Potsdam  Sandstone          .... 

—  960  feet 
—  2060  feet 

140  miles 
220  miles 

Crystalline  Rock       

unknown  depth 

unknown  distance 

Represent  the  same  three  wells  in  this  section. 


106 


EXPERIMENTS   WITH    CITY   GAS 

Purpose.     To  study  a  familiar  gas  to  learn  :  — 

(1)  Whether  it  has  a  color ; 

(2)  Whether  it  will  burn; 

(3)  Whether  it  will  allow  other  substances  to  burn  in  it. 

Material.  Pan  of  water,  glass  jar  or  bottle  with  wide  mouth,  a  piece  of  cardboard  or  a  glass  plate  to 
cover  the  jar,  rubber  tube,  wire,  matches,  candle,  supply  of  city  gas. 

Operation  and  Result.  Fill  the  jar  with  water,  then,  holding  the  glass  plate  carefully  over  its  mouth, 
quickly  place  it  upside  down  in  the  pan  of  water,  and  withdraw  the  glass  plate. 

1.  What  now  fills  the  jar? 

Connect  the  rubber  tube  with  the  gas  jet,  and,  placing  the  other  end  under  the  mouth  of  the  jar, 
allow  the  gas  to  run  into  it  until  all  the  water  is  driven  from  it.  Turn  off  the  gas,  withdraw  the  tube, 
slip  the  glass  plate  again  under  the  mouth  of  the  jar,  and,  holding  it  firmly,  lift  out  the  jar  and  place  it 
right  side  up  on  the  table. 

2.  What  now  fills  the  jar? 

3.  What  is  the  color  of  the  gas? 

Fasten  a  candle  to  a  wire  two  or  three  feet  long,  and  light  it.  Remove  the  glass  plate  and,  by 
means  of  the  wire,  quickly  lower  the  burning  candle  to  the  bottom  of  the  jar,  keeping  the  hands  a  foot 
or  more  away  from  it. 

4.  Does  the  gas  burn? 

5.  Does  the  candle  continue  to  burn? 

6.  Explain  the  action  of  the  candle. 

7.  Write  a  sentence  stating  what  you  have  learned  about  each  of  the  three  points  given  as  the  pur- 
pose of  this  experiment. 


Drawing.     On  the  lower  part  of  this  page,  draw  the  apparatus  used,  showing  the  results  of  lowering 
the  candle  into  the  jar. 


107 


EXPERIMENTS   WITH   OXYGEN 

Purpose.     To  prepare  the  gas  oxygen  and  to  learn :  — 

(1)  Whether  it  has  a  color ; 

(2)  Whether  it  will  burn  ; 

(3)  Whether  it  will  allow  other  substances  to  burn  in  it. 

Material.  Large  test  tube,  sodium  peroxide,  water,  long  splinter  of  wood  or  sticks  of  charcoal, 
picture  wire,  matches. 

Operation  and  Result.  Fill  the  test  tube  about  £  inch  deep  with  sodium  peroxide,  and  pour  a  little 
water  on  it. 

1.  What  happens  in  the  tube  ? 

.  The  cause  of  this  is  that  the  water  acts  chemically  on  sodium  peroxide,  setting  oxygen  gas  free. 

2.  What  is  the  color  of  the  gas  given  off  V     (Do  not  mistake  the  fine  spray  of  water  for  oxygen.) 

3.  Thrust  a  match  or  splinter,  burning  with  a  small  flame,  into  the  tube.     What  effect  on  the  flame? 
Does  the  gas  burn  ? 

4.  Heat  a  charred  splinter  or  a  stick  of  charcoal  until  it  glows,  and  then  hold  it  in  the  tube.     What 
occurs? 

5.  Hold  a  glowing  charcoal  stick  in  the  air  a  short  time.     What  occurs  ? 

If  necessary,  renew  vigorous  action  in  the  tube  by  pouring  in  a  little  more  water. 

6.  Fasten  a  small  splinter  in  the  end  of  a  straight  piece  of  picture  wire.     Light  and  hold  in  the  tube. 
What  occurs? 

7.  Compare  the  action  of  oxygen  with  that  of  city  gas. 


8.   What  advantages  result  from  having  the  atmosphere  composed  partly  of  oxygen  ? 

Drawing.     On  the  lower  part  of  this  page,  draw  the  apparatus,  showing  the  result  from  operation 
number  4. 


109 


EXPERIMENTS   WITH   NITROGEN 

Purpose.     To  secure  a  quantity  of  nitrogen  gas  from  the  atmosphere  and  to  determine: — 

(1)  Whether  it  has  a  color ; 

(2)  What  proportion  of  the  air  it  constitutes ; 

(3)  Whether  it  will  burn  ; 

(4)  Whether  it  will  allow  other  substances  to  burn  in  it. 

Material.  Pyrogallic  acid,  six-inch  test  tube,  glass  dish  half  filled  with  water,  matches,  ruler,  potas- 
sium hydroxide. 

Operation  and  Result.  Dissolve  a  piece  of  pyrogallic  acid,  the  size  of  a  pea,  in  about  a  tablespoonful 
of  water  in  a  test  tube.  Add  a  tablespoonful  of  strong  potassium  hydroxide  solution,  and  close  the 
tube  tightly  with  the  thumb. 

1.  What  substances  now  fill  the  tube  ? 

2.  Measure  and  state  the  depth  of  each. 

3.  Shake  the  tube  thoroughly  for  a  short  time,  and,  holding  it  upside  down  with  its  mouth  below 
the  surface  of  the  water  in  the  dish,  remove  the  thumb.      What  does  the  water  do? 

The  cause  is  that  the  acid  absorbs  the  oxygen.  The  vacancy  thus  made  is  filled  by  the  water 
pushed  in  by  the  pressure  of  the  outside  atmosphere.  The  gas  left  in  the  tube  is  nearly  pure  nitrogen. 
The  small  quantities  of  argon,  water  vapor,  and  carbon  dioxide  which  are  mixed  with  the  nitrogen  do 
not  affect  its  color  or  the  other  characteristics  investigated  below.  Replace  the  thumb  over  the  mouth 
of  the  tube,  take  it  from  the  dish,  and  hold  it  right  side  up. 

4.  What  is  the  color  of  nitrogen  ? 

5.  Measure,  and  state  the  depth  of  the  gas. 

6.  The  nitrogen  now  left  is  about  what  proportion  of  the  air  caught  at  first  in  the  tube? 

7.  Removing  the  thumb,  lower  a  burning  match  stick  into  the  tube.     Does  the  stick  continue  to 
burn  ? 

8.  Does  the  nitrogen  burn  ? 

9.  How  does  the  action  of  nitrogen  compare  with  that  of  city  gas? 


10.   Compare  its  action  with  that  of  oxygen. 


Drawing.     On  the  lower  part  of  this  page,  draw  a  test  tube  and  indicate  the  depth  of  air  in  it  at 
first ;  also  the  depth  of  nitrogen  left  from  it. 


Ill 


EXPERIMENTS   WITH   CARBON   DIOXIDE 

Purpose.     To  prepare  carbon  dioxide  and  to  learn  :  — 

(1)  Whether  it  has  color  ; 

(2)  Whether  it  will  burn  ; 

(3)  Whether  it  will  allow  other  substances  to  burn  in  it ; 

(4)  How  to  use  the  test  that  distinguishes  it  from  other  gases. 

Material.  Test  tube,  dilute  hydrochloric  acid,  small  pieces  of  marble,  matches,  rubber  cork  fitted 
with  a  short  glass  tube  ending  in  a  short  rubber  tube,  bottle  of  limewater. 

Operation  and  Result.     Put  the  marble  in  the  test  tube,  and  pour  a  little  acid  on  it. 

1.  What  happens  in  the  tube  ? 

The  cause  of  this  is  that  the  acid  acts  on  the  marble,  setting  carbon  dioxide  free. 

2.  What  is  the  color  of  the  gas  ? 

Lower  a  burning  match  stick  into  the  gas. 

3.  Does  the  stick  continue  to  burn  ? 

4.  Does  the  gas  burn  ? 

5.  Which  of  the  three  gases  previously  studied  does  carbon  dioxide  most  resemble  ? 

If  the  reaction  has  ceased,  add  more  acid.  Place  the  cork  with  its  connected  tubing  in  the  test  tube, 
and  let  the  free  end  of  the  rubber  tube  dip  in  the  bottle  of  limewater.  Allow  the  gas  to  bubble  through 
it  a  short  time. 

6.  What  happens  to  the  limewater? 

This  gas  is  the  only  one  in  the  atmosphere  that  affects  the  color  of  limewater. 

7.  Why  is  this  test  necessary  to  distinguish  this  gas  from  nitrogen  ? 

8.  What  other  test  will  distinguish  this  gas  from  oxygen  ? 

Drawing.  On  the  lower  part  of  this  page,  draw  the  entire  apparatus  used  when  trying  the  lime- 
water  test. 


113 


LIGHT.     THE   COLORS  IN  SUNLIGHT 

Purpose.     To  study  the  colors  that  compose  white  sunlight. 

Material.     Glass  prism,  sheet  of  white  cloth  or  paper,  mirror,  sunlight. 

Operation.  Paste  a  piece  of  paper  ou  one  face  of  a  prism  and  hold  this  face  horizontally  and  upper- 
most in  the  sunlight.  Instead  of  passing  through  the  prism  to  the  floor,  the  light  will  bend  away,  and 
can  be  made  to  fall  on  a  piece  of  white  cloth  or  paper  hung  on  the  opposite  wall  of  the  room.  Instead 
of  the  white  sunlight,  it  will  furnish  the  colors  of  the  rainbow.  This  is  called  the  spectrum.  The 
colors  will  appear  brighter  if  the  room  is  darkened,  and  a  sunbeam  is  admitted  through  a  hole  in  the 
shutter. 

1.  What  color  appears  at  the  bottom  of  the  spectrum?    At  the  top? 

2.  Name  all  the  colors  you  can  see  in  the  order  in  which  they  appear  from  the  bottom  to  the  top  of 
the  spectrum. 


3.  Make   a  diagram   to  show   the   ray  of   sunlight  passing 
through  the  prism  and  spreading  out  to  form  the  colors  on  the 
screen.     Which  color  has.  been  bent  the  most  from  the  original 
path  of  the  sunbeam  ?    Which  color  has  been  bent  the  least  ? 

4.  Hold  a  hand  mirror  near  the  prism  so  as  to  reflect  the 
spectrum  on  a  wall  or  ceiling.     Give  a  rapid  vibrating  motion  to 

the  mirror  so  that  the  spectrum  moves  to  and  fro  very  quickly  in  the  direction  of  its  length,  and  forms 
a  streak  of  light.     What  is  its  color  ?    What  has  become  of  the  spectrum  ? 

5.  Observe  the  sunrise  and  sunset  colors,  and  report  their  arrangement.     Which  color  of  the  spec- 
trum is  below  ?    Explain. 


6.   Observe  the  colors  in  a  rainbow.     Report  the  arrangement  of  colors,  and  the  location  of  the  sun 
and  of  the  rainbow  with  regard  to  your  position.     Give  drawings. 


LIGHT.     ABSORPTION  OF  COLORS 

Purpose.  To  learn  how  some  of  the  colors  of  the  sunlight  may  be  absorbed  by  passing  through  a 
substance  or  by  being  reflected  from  it. 

Material.     Flat-sided  bottle,  soap  solution,  piece  of  smoked  glass. 

Operation.  Fill  a  flat-sided  bottle  with  water  in  which  laundry  soap  has  been  dissolved.  Look 
through  it  toward  the  sunlight  while  slowly  rotating  it. 

1.  What  colors  come  through  it  to  your  eye? 

2.  Hold  the  bottle  toward  some  dark  object,  as  the  blackboard,  so  that  the  light  is  reflected  from 
the  soap  solution  to  you.     What  is  the  color? 

3.  Then  what  colors  have  been  absorbed  by  the  soap  solution? 

The  soap  solution  acts  like  the  atmosphere  in  allowing  one  or  two  colors  to  pass  through  it  easily, 
and  in  reflecting  another  color. 

115 


4.  What  seems  to  be  the  color  of  the  sun  when  its  light  comes  to  us  through  a  clouded  or  hazy  sky  V 

5.  Must  the  deep  blue  color  of  the  northern  sky  be  due  to  sunlight  coining  through  it,  or  the  reflec- 
tion from  particles  in  the  atmosphere  ? 

6.  Look  toward  the  sun  through  the  smoked  glass.     What  is  the  sun's  color  when  seen  through  a 
part  of  the  glass  that  has  been  heavily  smoked?     Lightly  smoked? 

7.  Does  the  sunlight,  in  reaching  you,  pass  through  more  of  the  atmosphere's  smoke  and  dust  at 
noon  or  at  sunset  ? 

What  effect  has  this  upon  the  color? 


116 


ATMOSPHERIC   PRESSURE 

Purpose.    To  determine  whether  the  atmosphere  exerts  pressure. 

Material.  A  tin  can  with  a  small  mouth,  a  cork  to  fit  it,  water,  gas  burner,  support,  glass  thistle 
tube  with  a  short  rubber  tube  attached,  sheet  of  dentists'  rubber,  string. 

Operation  and  Result.  A.  Put  a  little  water  in  the  can  and  support  it  over  a  lighted  burner  until 
the  water  has  boiled  vigorously  for  a  few  minutes.  Turn  out  the  burner  and,  at  the  same  moment,  close 
the  can  firmly  with  the  cork.  Allow  the  can  to  cool,  and  note  what  happens.  The  cooling  may  be 
hastened  by  sprinkling  water  on  the  can. 

1.  Describe  the  result. 

2.  What  did  the  steam,  rising  from  the  surface  of  the  water,  do  to  the  air  in  the  can? 

3.  When  the  can  cooled,  what  became  of  the  steam? 

4.  What  made  the  can  collapse? 

5.  Make  a  section  drawing  of  the  can  when  the  water  was  boiling.     By 
means  of  arrows  show  the  direction  in  which  the  steam  moves  within  the  can. 

B.   Lay  a  sheet  of  dentists'  rubber  over  the  mouth  of  a  thistle  tube,  and  tie  it  fast  with  a  string. 

6.  Blow  into  the  tube.     Is  the  dentists'  rubber  pushed  outward  or  pulled  outward? 

7.  With  the  mouth,  draw  air 'out  of  the  thistle  tube,  and  pinch  the  attached  rubber  tube  tightly  to- 
gether.    Is  the  dentists'  rubber  pulled  inward  or  pushed  inward  ? 

State  why  you  think  so. 

8.  Still  pinching  the  rubber  tube  tightly,  turn  the  thistle  tube  in  various  directions.     In  how  many 
directions  does  the  air  exert  pressure? 

In  what  directions  does  the  pressure  seem  to  be  equal  ? 

9.  Make  a  drawing  of  the  apparatus,  showing  the  result  of  drawing  out  the  air,  using  arrows  to 
show  the  direction  of  air  pressure. 


117 


COLUMNS   OF   MERCURY  AS   INDICATORS   OF   AIR   PRESSURE 

Purpose.     To  learn  how  columns  of  mercury  may  be  used  to  indicate  air  pressure. 

Material.  Mercury,  bottle  fitted  with  a  two-hole  stopper,  rubber  tube,  a  short  and  a  long  glass 
tube  to  fit  the  holes  in  the  stopper,  two  glass  tubes  of  the  same  length  but  of  different  diameters,  a 
T-tube  having  short  rubber  tubes  attached. 

Operation  and  Result.  Fill  the  bottle  an  inch  or  two  deep  with  mercury.  Push  the  short  glass 
tube  barely  through  one  hole  of  the  stopper.  Push  the  long  tube  far  enough  through  the  other  hole  to 
reach  to  the  bottom  of  the  bottle.  Place  the  stopper  in  the  bottle. 

1.  How  high  does  the  mercury  stand  in  this  long  tube  ? 

2.  Attach  the  rubber  tube  to  the  short  glass  tube,  and  blow  through  it  into  the  bottle.     What  does 
the  mercury  do  ?     Why? 


3.  What  determines  the  height  of  the  mercury  ? 

4.  Remove  the  rubber  tube  and  attach  it  to  the  long  tube.     With  the  mouth,  draw  the  air  out 
of  the  tube.     What  does  the  mercury  do  ?    Why  ? 


5.  Make  a  section  drawing  of  the  apparatus  to  show  the 
result  in  question  4,  using  arrows  to  show  where  the  air  exerts 
pressure. 

6.  Remove  the  stopper.    Stand  the  two  tubes  having  differ- 
ent diameters  vertically  in  the  bottle,  and  connect  their  upper 
ends  with  the  T-tube.     With  the  mouth,  draw  the  air  from  the 
T-tube  and  observe  the  result.     Does  the  mercury  rise  to  the 
same  level  or  to  different  levels? 

7.  If  one  of  the  tubes  had  been  one  inch  square,  would  the 
mercury  have  risen  to  the  same,  height  in  it  as  in  the  other 
tube? 

8.  Make  a  section  drawing  of  the  apparatus  described  in  question  6,  and  show  the  result  of  the  ex- 
periment. 


119 


MAKING   A   MERCURIAL   BAROMETER 

Purpose.     To  make  a  mercurial  barometer. 

Material.     A  glass  tube  about  36  inches  long  closed  at  one  end,  glass  tumbler,   mercury,  glass 
funnel  fitted  with  a  short  rubber  tube  ending  in  a  short  pointed  glass  tube,  ruler,  support. 
Operation  and  Result.     Place  the  glass  tube,  open  end  up,  in  the  support. 

1.  What  now  fills  the  tube? 

Tightly  pinching  the  short  rubber  tube,  fill  the  funnel  half  full  of  mercury,  and,  inserting  the 
pointed  tip  in  the  long  glass  tube,  allow  a  fine  stream  of  mercury  to  run  until  the  tube  is  completely 
filled.  Holding  a  finger  firmly  over  the  open  end  of  the  tube,  invert  it  into  a  glass  cup  filled  about  an 
inch  deep  with  mercury.  Holding  the  tube  erect,  and  watching  carefully  the  upper  end  of  the  mer- 
cury, remove  the  finger. 

2.  Describe  the  result. 


3.  Measure  and  state  how  many  inches  high  the  mercury  stands  above  the  mercury  in  the  cup. 

4.  Is  there  any  air  in  the  space  in  the  upper  part  of  the  tube  ?    State  why  you  think  so. 

5.  Does  the  weight  of  any  substance  bear  on  the  surface  of  the  mercury  in  the  cup? 

6.  What,  therefore,  must  hold  up  the  mercury  in  the  tube? 

7.  Why  must  the  barometer  tube  be  closed  at  the  top? 

8.  If  you  had  used  a  square  barometer  tube  1  inch  across,  and  36  inches  long,  how  high  would  the 
column  of  mercury  have  stood? 

9.  Since  1  cubic  inch  of  mercury  weighs  about  |  pound  (strictly  .49  pound),  what  does  this  ex- 
periment show  the  weight  of  the  air  to  be  on  1  square  inch  of  surface? 

10.  Carefully  make  a  drawing  of  the  apparatus,  showing  the  result. 


121 


THE   ACTION   OF   A   BAROMETER 

Purpose.     To  learn  the  action  and  practical  use  of  a  barometer. 

Material.  The  barometer  made  in  the  previous  experiment,  a  wide-mouth  Mason  jar,  a  rubber 
cork  having  a  short  glass  tube  through  it  to  which  is  fitted  a  rubber  tube  two  or  three  feet  long,  wax, 
strong  string. 

Operation  and  Result.  Break  the  porcelain  plate  out  of  the  lid  of  the  jar.  Punch  two  holes  in  the 
metal  top,  one  slightly  larger  than  the  barometer  tube,  the  other  large  enough  to  hold  the  rubber 
stopper ;  or  use  a  wide-mouth  bottle  with  a  two-hole  rubber  stopper. 

Tie  the  cord  around  the  glass  cup  (a  small  beaker  works  nicely)  and  lower  the  barometer  into 
the  jar.  Slip  the  cover  down  over  the  barometer  tube  and  screw  it  tightly  on  the  jar.  Carefully  seal 
the  opening  around  the  barometer  tube  with  wax  or  chewing  gum.  Push  the  cork  holding  -the  short 
tube  tightly  into  the  other  hole. 

1.   Blow  into  the  rubber  tube.     "What  does  the  column  of  mercury  do  ?    Why? 


2.   Draw  air  out  of  the  tube.     What  does  the  mercury  do  ?    Why  ? 


On  this  page  draw  a  vertical  section  of  the  entire  apparatus.  Mark  and  name  the  place  where  the 
mercury  stood  (a)  at  the  beginning  of  the  experiment,  (6)  after  blowing  more  air  into  £he  jar,  (c)  after 
drawing  some  air  out  of  the  jar. 


123 


CONDITIONS   AFFECTING   EVAPORATION 

Purpose.     To  learn  the  conditions  affecting  evaporation. 

Material.     Tin  cups  or  beakers,  small  pan,  glass  plates,  tumbler,  water,  piece  of  iron,  gas  burner. 

Operation  and  Result.  A.  Put  five  drops  of  water  on  a  glass  plate  and  place  it  on  a  warm  piece  of 
iron.  Put  the  same  amount  on  another  glass  plate  and  place  it  on  the  desk.  Be  careful  to  keep  both 
plates  away  from  a  draught. 

1.  Which  evaporates  faster?     Why? 

B.  Secure  two  other  glass  plates  and  place  five  drops  of  water  on  each.     Place  one  plate  in  a 
draught  or  fan  it  some  minutes. 

2.  Which  evaporates  faster  ?    Why  ? 

C.  In  two  small  cups  or  beakers  place  equal  amounts  of  water.     Cover  one  cup  with  an  inverted 
tumbler. 

3.  What  collects  on  the  inside  of  the  tumbler  ? 

4.  Is  the  air  within  the  tumbler  damp  or  dry  ? 

5.  From  which  cup  does  water  evaporate  faster  ?    Why  ? 

D.  Put  equal  amounts  of  water  into  a  pan  and  into  a  small  cup  (enough  to  cover  the  bottom  of 
the  pan).     Allow  the  vessels  to  remain  close  together  until  you  have  clearly  determined  from  which 
vessel  the  water  evaporates  faster. 

6.  What  causes  the  difference  ? 

In  one  sentence,  state  the  four  conditions  learned  from  this  experiment,  that  aid  evaporation. 


EFFECTS   OF   EVAPORATION 

Purpose.  To  learn  how  the  temperature  of  an  object  is  affected  when  a  liquid  evaporates  from 
its  surface. 

Material.     Two  thermometers  of  the  same  style  and  size,  sulphuric  ether  or  alcohol,  water. 

Operation  and  Result.  First  note  the  temperature  of  the  thermometer,  then  put  drop  after  drop  of 
ether  on  the  bulb,  recording  the  temperature  after  each  drop  has  evaporated. 

1.  What  is  the  general  effect  on  the  thermometer?    Is  the  change  rapid  or  slow? 

2.  Where  does  part  of  the  heat  come  from  that  is  absorbed  by  the  ether  in  evaporating? 

Allow  drops  of  water  as  warm  as  the  room  to  evaporate  on  the  bulb  of  another  thermometer.  Record 
the  temperature  after  each  drop. 

3.  Compare  the  change  in  temperature  with  that  caused  by  the  evaporation  of  ether. 

4.  Draw  the  thermometers  on  the  lower  part  of  this  sheet,  indicating  the  temperature  at  the 
beginning  and  at  the  end  of  the  experiment  with  the  ether,  and  also  with  the  water. 


125 


CONDENSATION   OF    WATER   VAPOR 

Purpose.     To  learn  the  conditions  ttiat  cause  the  condensation  of  vapor. 

Material.     Erlenmeyer  flask,  water,  gas  burner,    glass  plate,  bright  tin  cup,  salt,  ice  or  snow. 

Operation  and  Result.     A.     Heat  some  water  in  a  flask  until  it  boils. 

1.  What  is  the  color  of  the  vapor  or  steam  in  the  flask? 

2.  What  shows  that  a  change  occurs  in  the  steam  as  it  rises  in  the  air  ?    What  causes  the  change? 

3.  Hold  a  cool  glass  plate  just  above  the  flask.     What  does  it  do  to  the  vapor?    Why? 

4.  Which  part  of  this  experiment  illustrates  the  formation  of  fog  off  the  coast  of  Labrador? 

5.  Which  part  illustrates  the  formation  of  fog  on  a  mountain  slope  ? 

B.    Thoroughly  dry  the  outside  of  the  cup  and  half  fill  it  with  water.     Put  in  some  ice  or  snow,  a 
little  at  a  time,  and  stir  with  a  thermometer. 

6.  What  forms  on  the  outside  of  the  cup  ? 

7.  Where  does  it  come  from  ? 

8.  Why  does  it  form  ? 

9.  At  about  what  temperature  is  the  cup  when  condensation  begins  ?     (This  is  called  the  "  dew 
point.") 

10.  In  a  cup  dry  outside,  place  some  finely  broken  ice  or  snow  mixed  with  salt.     Stir  with  a  ther- 
mometer and  note  the  temperature  when  frost  forms  on  the  outside.     Did  dew  form  on  the  outside 
before  the  frost  appeared? 

1 1.  Would  dew  form  before  frost  in  very  dry  weather  ? 

12.  What  is  the  difference  between  frozen  dew  and  hoarfrost? 


127 


FORMATION   OF   FOG  AND   CLOUD 

Purpose.  To  learn  how  the  moisture  and  the  temperature  of  the  air  are  affected  by  changes  in  the 
pressure  of  the  atmosphere. 

Material.  Large  bottle,  two-hole  rubber  stopper,  thermometer,  water,  matches,  air  pump  or  bicycle 
pump,  and  rubber  tubing. 

Operation  and  Result.  Put  a  little  water  in  the  bottle  to  furnish  moisture.  Insert  the  thermometer 
in  one  hole  of  the  stopper  so  that  the  bulb  will  be  within  the  bottle.  Through  the  other  hole,  insert 
the  tube  and  connect  it  with  a  bicycle  pump  or  atomizer  bulb.  Pump  air  into  the  bottle  and  then 
suddenly  disconnect  the  tube. 

1.  What  does  the  surplus  air  do  ?    What  does  some  of  the  vapor  do  ? 

Drop  a  burning  match  into  the  bottle  to  supply  a  little  smoke  or  "  dust,"  and  repeat  the  operation. 

2.  What  result?    Why  different  from  the  first  trial  V 


3.   Pump  air  in  again.     What  effect  on  the  thermometer?     On  the  fog?     Explain  both. 


4.  Since  rising  air  expands,  why  do  upward-moving  currents  of  air  produce  clouds  and  rain  V 

5.  Draw  the  apparatus  on  this  sheet. 


129 


MOISTURE    IN   THE   ATMOSPHERE.     RELATIVE  HUMIDITY 


Purpose.     To  determine  to  what  extent  the  air  of  the  room  is  saturated. 

Materials.  Two  thermometers,  piece  of  ca'rdboard  a  little  longer  than  the  thermometers,  vial, 
small  piece  of  muslin,  water,  thread. 

Directions.  Wrap  one  end  of  the  muslin  around  the  bulb  of  one  thermometer,  tying  it  with  thread 
so  that  the  muslin  shall  hang  down  two  or  three  inches  like  a  wick.  Tie  the  thermometer  and  the  vial 
to  the  cardboard  so  that  the  wick  shall  hang  in  the  vial.  Fasten  the  dry-bulb  thermometer  to  the 
same  cardboard.  Wet  the  muslin  and  fill  the  vial  with  water  that  has  been  standing  in  the  room  long 
enough  to  have  the  room's  temperature.  Fan  the  thermometer  and  note  the  readings. 

1.  Which  thermometer  shows  the  cooler  temperature ?     Why  does  it? 

2.  Would  the  water  evaporate   from  the   cloth  faster  in  dry  or  in  damp  air?    Then  would  the 
thermometers  differ  more  in  dry  or  in  damp  air  ?     Why  ? 

3.  If   the  thermometers    are  not   fanned,  will    the   air    around  them  remain  as  dry  as  the  air 
throughout  the  room  ?     Explain. 

4.  Of  what  does  the  dry  thermometer  show  the  temperature?    Does  fanning  change  it? 

The  following  table  will  show  to  what  per  cent  the  air  is  saturated.  In  the  left-hand  vertical  column, 
find  the  temperature  registered  by  the  dry  thermometer.  At  the  top  of  the  vertical  columns,  find  the  num- 
ber which  shows  the  difference  in  the  readings  of  your  two  thermometers.  From  this  number,  follow 
down  the  column  to  the  line  indicated  by  the  dry  thermometer.  The  figure  at  the  intersection  shows  the 
per  cent  of  saturation. 

.    TABLE   FOR   FINDING   RELATIVE   HUMIDITY —  PERCENTAGES 


Dry 
Therm. 
(Air 
Temp.1* 

Difference  between  Dry-  and  Wet-bulb  Thermometers 
1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21 

30 

89 

78 

68 

57 

47 

37 

27 

17 

8 

32 

90 

79 

69 

60 

50 

41 

31 

22 

13 

4 

34 

90 

81 

72 

62 

53 

44 

35 

27 

18 

9 

1 

36 

91 

82 

73 

65 

56 

48 

39 

31 

23 

14 

6 

38 

91 

83 

75 

67 

59 

51 

43 

35 

27 

19 

12 

4 

40 

92 

84 

76 

68 

61 

53 

46 

38 

31 

23 

16 

9 

2 

42 

92 

85 

77 

70 

62 

55 

48 

41 

34 

28 

21 

14 

7 

0 

44 

93 

85 

78 

71 

64 

57 

51 

44 

37 

31 

24 

18 

12 

5 

46 

93 

86 

79 

72 

65 

59 

53 

46 

40 

34 

28 

22 

16 

10 

4 

48 

93 

87 

80 

73 

67 

60 

54 

48 

42 

36 

31 

25 

19 

14 

8 

3 

50 

93 

87 

81 

74 

68 

62 

56 

50 

44 

39 

33 

28 

22 

17 

12 

7 

2 

52 

94 

88 

81 

75 

69 

63 

58 

52 

46 

41 

36 

30 

25 

20 

15 

10 

6 

0 

54 

94 

88 

82 

76 

70 

65 

59 

54 

48 

43 

38 

33 

28 

23 

18 

14 

9 

5 

0 

56 

94 

88 

82 

77 

71 

66 

61 

55 

50 

45 

40 

35 

31 

26 

21 

17 

12 

8 

4 

58 

94 

89 

83 

77 

72 

67 

62 

57 

52 

47 

42 

38 

33 

28 

24 

20 

15 

11 

7 

3 

60 

94 

89 

84 

78 

73 

68 

63 

58- 

53 

49 

44 

40 

35 

31 

27 

22 

18 

14 

10 

6 

2 

62 

94 

89 

84 

79 

74 

69 

64 

60 

55 

50 

46 

41 

37 

33 

29 

25 

21 

17 

13 

9 

6 

64 

95 

90 

85 

79 

75 

70 

(56 

61 

56 

52 

48 

43 

39 

35 

31 

27 

23 

20 

16 

12 

9 

66 

95 

90 

85 

80 

76 

71 

66 

62 

58 

53 

49 

45 

41 

37 

33 

2!) 

26 

22 

18 

15 

11 

68 

95 

90 

85 

81 

76 

72 

67 

63 

59 

55 

51 

47 

43 

39 

35* 

31 

28 

24 

21 

17 

14 

70 

95 

90 

86 

81 

77 

72 

68 

64 

60 

56 

52 

48 

44 

40 

37 

33 

30 

26 

23 

20 

17 

72 

95 

91 

86 

82 

78 

73 

69 

65 

61 

57 

53 

49 

4(5 

42 

39 

35 

32 

28 

25 

22 

19 

74 

95 

91 

86 

82 

78 

74 

70 

66 

62 

58 

54 

51 

47 

44 

40 

37 

34 

30 

27 

24 

21 

76 

96 

91 

87 

83 

78 

74 

70 

67 

63 

59 

55 

52 

48 

45 

42 

38 

SB 

32 

29 

26 

23 

78 

96 

91 

87 

83 

79 

75 

71 

67 

64 

60 

57 

53 

60 

46 

43 

40 

37 

34 

31 

28 

25 

80 

96 

91 

87 

83 

79 

76 

72 

68 

64 

61 

57 

'54 

51 

47 

44 

41 

38 

35 

32 

29 

27 

82 

96 

91 

87 

83 

79 

76 

72 

69 

ft5 

62 

58 

55 

52 

49 

46 

43 

40 

37 

34 

31 

28 

84 

96 

92 

88 

84 

80 

77 

73 

70 

66 

63 

59 

56 

53 

50 

47 

44 

41 

38 

35 

32 

30 

86 

96 

92 

88 

84 

80 

77 

73 

70 

66 

63 

60 

57 

54 

51 

48 

45 

42 

39 

37 

34 

31 

88 

96 

92 

88 

85 

81 

78 

74 

71 

67 

64 

61 

58 

55 

52 

49 

46 

43 

41 

38 

35 

33 

90 

96 

92 

88 

&5 

81 

78 

74 

71 

68 

64 

61 

58 

56 

53 

50 

IT 

44 

42 

.SO 

37 

34 

92 

96 

92 

89 

85 

82 

78 

75 

72 

69 

65 

62 

59 

57 

54 

51 

48 

45 

43 

40 

88 

35 

94 

96 

92 

89 

85 

82 

78 

75 

72 

69 

66 

63 

60 

57 

54 

52 

49 

4<i 

44 

41 

89 

36 

96 

96 

93 

89 

86 

82 

79 

76 

73 

70 

67 

64 

61 

58 

55 

53 

50 

47 

45 

42 

40 

37 

98 

96 

93 

89 

86 

82 

79 

76 

73 

70 

67 

64 

61 

58 

56 

53 

51 

48 

46 

43 

41 

39 

100 

96 

93 

90 

86 

83 

80 

77 

74 

71 

88 

65 

62 

59 

57 

54 

52 

49 

47 

44 

42 

40 

131 


Test  the  humidity  on  five  different  dates  and  record  as  follows  :  — 


DATE 


TEMP.  OF  THE 
AIR  (DRY  THER.) 


WET-BULB 
KK  APING 


DIFFERENCE 
IN  TEMPERATURE 


PER  CENT  OF  SATURATION 
(RELATIVE  HUMIDITY  i 


132 


MOISTURE   IN   THE   ATMOSPHERE  —  ABSOLUTE   HUMIDITY 

Purpose.     To  determine  the  actual  weight  of  water  vapor  in  one  cubic  foot  of  air. 

The  amount  of  water  vapor  in  one  cubic  foot  of  saturated  air  changes  with  the  temperature.  The 
actual  amount  at  different  temperatures  is  shown  in  grains  in  the  following  table.  One  grain  of 
vapor  condensed  to  water  would  form  a  drop  about  the  size  of  a  grain  of  wheat.  In  the  vapor  form  it 
occupies  a  much  larger  space. 

GRAINS  OF  SATURATED  WATER  VAPOR  PER  CUBIC  FOOT 


At    0°,    .5  grain 
At  10°,    .8  grain 
At  20°,  1.2  grains 
At  30°,  2.0  grains 

At  40°,  2.8  grains 
At  50°,  4.0  grains 
At  60°,  5.7  grains 
At  70°,  8.0  grains 

At  80°,    11.0  grains 
At  90°,    14.8  grains 
At  100°,  19.8  grains 

Problems.     1.   What  is  the  largest  number  of  grains  of  water  vapor  that  one  cubic  foot  of  air  can 
hold  at  0°?    30°?    50°?    70°?     100°? 

2.  How  many  additional  grains  of  vapor  would  a  cubic  foot  of  air  be  able  to  hold  if  warmed  from 
20°  to  30°  ?    If  warmed  from  90°  to  100°  V 

3.  When  saturated  air  cools,  all  the  vapor  it  cannot  hold  condenses  to  snow  or  water.     How  many 
grains  of  moisture  would  be  condensed  from  one  cubic  foot  of  saturated  air  if  it  cooled  from  90°  to  80°? 
If  from  40°  to  30°?    If  from  10°  to  0°? 

4.  If  1200  cubic  feet  of  saturated  air  cools  from  50°  to  10°,  how  many  grains  of  water  and  how 
many  of  snow  will  be  formed  ? 

5.  Is  the  air  able  to  contain  more  vapor  near  the  equator  or  near  the  poles?     At  which  of  these 
places  would  cooling  produce  a  heavier  rainfall  ? 

6.  If  air  were  50%  saturated,  how  many  grains  of  vapor  would  be  in  one  cubic  foot  of  air  at  50°? 
At  90°? 

7.  With  a  relative  humidity  of  60%  and  a  temperature  of  70°,  how  many  grains  of  water  vapor  in 
500  cubic  feet  of  air?    In  the  air  of  your  schoolroom  under  the  same  conditions? 

8.  San  Francisco  and  Independence,  Cal.,  have  the  same  average  temperature  of  60°.     The  relative 
humidity  of  the  former  is  77%,  and  of  the  latter,  37%.     Notice  their  location  on  a  map  and  explain  this 
difference  in  amount  of  moisture.     How  many  grains  of  vapor  in  one  cubic  foot  of  air  at  each  place?    I  n 
which  place  would  cooling  the  same  number  of  degrees  produce  the  heavier  rainfall? 

9.  The  average  temperature  of  Chicago  is  50°,  and  of  Yuma,  Ariz.,  is  70°.     The  average  relative 
humidity  of  the  former  is  77%,  and  of  the  latter,  49%.    What  is  the  average  weight  of  water  vapor  in  a 
cubic  foot  of  air  at  each  place?    Which  has  the  greater  amount?     Why.  therefore,  has  Chicago  a  much 
heavier  rainfall  than  Yuma? 

10.  On  a  sheet  of  cross-section  paper,  draw  a  chart  to  show  how  much  more  vapor  the  air  can  hold 
as  it  becomes  warmer.     Let  the  lowest  hori/ontal  line  represent  the  temperature  of  zero  degrees.     Let 
one  small  square  vertically  represent  one  degree.     Write  the  proper  degree  of  temperature  in  the  side 
margin,  at  the  end  of  each  heavy  horizontal  line.     To  show  the  amount  of  water  vapor,  let  one  centi- 
meter horizontally  represent  one  grain.    Label  the  heavy  line  at  the  binding  margin  "0  grains,"  the 
next  heavy  vertical  line  "  1  grain,"  etc.,  across  the  top  of  the  sheet.     Using  the  above  table,  place  a  dot 
to  show  the  number  of  grains  of  water  vapor  that  air  can  hold  at  each  temperature  given.     Connect  these 
dots  with  a  curving  line,  and  color  the  space  between  it  and  the  binding  margin.     Label  it  "  Grains 
of  Water  Vapor  Air  can  hold  at  Different  Temperatures." 


134 


EXPERIMENTS   WITH   HEAT 

A 

Purpose.     To  learn  the  effect  of  heat  upon  the  size  of  a  solid. 

Material.     Solid  brass  ball,  ring  just  large  enough  to  allow  the  ball  to  pass  through  it,  gas  burner. 
Operation  and  Result.     Note  how  closely  the  ring  fits  the  ball.     Heat  the  ball  for  a  few  minutes, 
testing  its  size  at  frequent  intervals  by  trying  to  pass  it  through  the  ring. 

1.  What  do  these  tests  prove  ? 

Allow  the  ball  to  cool,  testing  its -size  at  frequent  intervals. 

2.  What  do  these  tests  prove  ? 

3.  Similar  changes  in  size  are  caused  by  temperature  changes  in  rocks,  glass,  and  other  solids. 
Explain  why  the  outside  layer  sometimes  snaps  off  from  a  rock  exposed  to  the  sun. 


B 

Purpose.     To  learn  the  effect  of  heat  upon  the  size  of  a  liquid. 

Material.  Colored  water,  Eiienmeyer  flask,  one-hole  rubber  cork,  glass  tube  at  least  15  inches  long, 
iron  support,  wire  gauze,  gas  burner,  rubber  bands,  foot  ruler. 

Operation  and  Result.  Fill  the  flask  with  colored  water.  Push  the  long  tube  nearly  through  the 
cork.  Adjust  the  cork  in  the  flask  so  that  the  water  shall  rise  a  short  distance  in  the  tube.  With  the 
rubber  bands,  fasten  the  ruler  to  the  long  tube  with  its  zero  end  even  with  the  top  of  the  column  of 
water.  Lay  the  wire  gauze  on  the  iron  support,  placing  the  flask  on  it,  and  a  lighted  burner  under  it. 

1.   What  is  the  first  brief  effect  on  the  height  of  the  water?     Explain  this. 


2.   Continue  to  warm  the  water.     Note  the  general  effect,  or 
record  the  time  required  for  each  increase  of  one  half  inch. 


3.  Allow  the  water  to  cool  for  a  time  and  note  the  effect. 

4.  What   effect   has   heat   upon   the  volume  of  the  water? 
Upon  its  density?     Upon  its  weight  per  cubic  inch? 

5.  On  the  margin  of  this  paper,  carefully  draw  the  apparatus 
used  in  this  experiment,  showing  the  height  of  the  water  before 
and  after  heating. 

6.  If  mercury,  alcohol,  and  other  liquids  were  substituted  for 
the  water  in  this  experiment,  they  would  behave  in  a  similar 
manner.     Explain  the  action  of  a  common  thermometer. 


135 


Purpose.     To  learn  the  effect  of  heat  upon  the  volume  of  a  gas. 

Material.  A  hollow  glass  globe  with  glass  tube  attached  ;  or  a  flask  (or  large  test  tube)  lilted  \\  it  h 
a  rubber  cork  through  which  passes  a  glass  tube;  cup  of  colored  water  ;  gas  burner. 

Operation  and  Result.  Hold  the  apparatus  so  that  the  end  of  the  glass  tube  dips  in  the  colored 
water. 

1.  What  now  fills  the  globe  (or  flask)  ? 

2.  Warm  the  globe  with  the  hands.     What  happens  in  the  water? 

3.  Carefully  bring  the  lighted  burner  near  the  globe.     What  effect  do  you  notice  ?    Explain  it. 


4.  Keeping  the  end  of  the  tube  in  the  water,  allow  the  globe 
to  cool.     What  does  the  water  do  ? 

What  must  the  air  in  the  globe  be  doing? 

5.  Clearly  state  the  effect  of  heat  upon  the  volume  of  a  gas. 

6.  What  must  be  the  effect  upon  its  density? 

7.  In  the  margin  draw  the  apparatus. 

D 

Purpose.     To  learn  how  heat  travels  through  solids. 

Material.     Bits  of  wood,  paraffin  or  wax,  metal  rod  or  wire,  gas  burner,  cardboard. 

Operation  and  Result.  Dip  the  bits  of  wood  in  wax  or  melted  paraffin,  and  attach  them  to  the  rod, 
placing  them  one  inch  apart.  Carefully  shielding  the  attached  pieces  from  the  direct  heat  of  the  burner 
by  means  of  the  cardboard,  heat  one  end  of  the  rod. 

1.   What  do  the  bits  of  wood  do?    What  does  this  prove  about  the  heat? 


2.  What  name  is  applied  to  this  method  of  heat  movement? 

3.  Where  in  nature  does  heat  travel  through  soliiN  '.' 

4.  On  the  lower  part  of  this  sheet,  make  a  drawing  of  the  apparatus. 


136 


E 


Purpose.     To  learn  how  heat  travels  through  liquids. 

Material.     Long  pan,  gas  burner,  bits  of  paper,  thermometer,  water. 

Operation  and  Result.  Nearly  fill  the  pan  with  water  and  support  it  a  few  inches  above  the  desk. 
Let  it  stand  until  the  water  is  perfectly  quiet,  then  sprinkle  the  bits  of  paper  on  the  water.  Hang  a 
thermometer  in  the  water  at  one  end  of  the  pan,  and  place  a  lighted  burner  under  the  other  end. 

1.   What  does  the  water  begin  to  do  ?    How  do  you  know  it  ? 


2.  As  the  water  near  the  burner  becomes  warmer,  does  it  expand  or  contract?    Does  it  become 
heavier  or  lighter  ? 

3.  What  has  this  change  to  do  with  the  movement  of  the  water? 


4.  How  is  the  thermometer  affected  ?     If  desired,  record  the  temperature  every  few  minutes. 

5.  How  does  the  heat  get  to  the  thermometer? 

6.  What  name  is  applied  to  this  method  of  heat  movement? 

7.  Name  some  countries  bordering  the  ocean  that  have  heat 
brought  to  them  from  equatorial  regions  by  this  method. 


8.   In  the  margin  draw  the  apparatus. 


F 


Purpose.     To  learn  one  method  by  which  heat  travels  through  gases. 

Material.  Candle,  matches,  shallow  pasteboard  box,  two  Argand  lamp  chimneys,  touch  paper 
(paper  soaked  in  a  solution  of  saltpeter  and  dried)  or  any  other  material  that  gives  off  much  smoke 
when  burning. 

Operation  and  Result.  Near  each  end  of  the  cover  of  the  box,  draw  a  circle  as  large  as  the  base  of 
the  lamp  chimney.  With  a  pencil,  punch  as  many  holes  as  possible  within  the  area  of  each  circle. 
Put  a  lighted  candle  in  the  center  of  one  group  of  holes,  and  then  place  the  chimneys  on  the  circles. 
Light  the  touch  paper  and  hold  it  above  each  chimney  in  turn. 

1.   What  does  the  air  in  the  chimneys  do,  and  how  do  you  know  it? 


2.   As  the  air  near  the  candle  becomes  warm,  does  it  expand  or  contract  ?    Does  it  become  lighter 
or  heavier?     Why  does  it  move? 


137 


3.  Hold  a  hand  above  each  chimney.     Which  is  the  warmer  ?    Explain  how  heat  gets  to  your  hand, 
and  give  the  proper  name  to  this  method  of  heat  movement. 

4.  In  what  part  of  your  apparatus  does  the  air  illustrate  the  movement  of  the  air  in  the  neighbor- 
hood of  the  earth's  heat  equator  ? 

5.  Where  does  the  air  illustrate  the  trade  winds  blowing  toward  the  equator? 

6.  Where  and  how  does  it  illustrate  the  air  in  the  tropical  calms  ? 

7.  Draw  a  vertical  section  of  your  apparatus,  and  with  arrows  show  the  movement  of  the  air. 


G 

Purpose.     To  learn  whether  heat  travels  through  a  vacuum. 

Material.     Electric  current;  incandescent  lamp  from  which  the  air  has  been  completely  exhausted. 

Operation  and  Result.     Hold  the  bulb  in  your  hand  and  turn  on  the  current. 

1.  What  change  in  temperature  do  you  notice? 

Although  the  bulb  has  no  air  in  it,  yet  its  space  is  filled  with  the  mysterious  ether  that  extends 
through  the  universe. 

2.  How  does  this  experiment  illustrate  the  earth's  receiving  light  and  heat  from  the  sun? 

3.  What  name  is  applied  to  this  method  of  heat  movement? 

4.  By  this  method,  heat  (and  light)  travels  186,000  miles  per  second.     State  the  sun's  average 
distance  from  us,  and  determine  how  many  minutes  are  required  for  the  sun's  rays  to   reach  the 
earth. 

II 

Purpose.     To  determine  whether  dark-  or  light-colored  surfaces  absorb  heat  most  readily. 

Material.     Two  thermometers,  sheet  of  cardboard,  small  piece  of  black  and  of  white  paper. 

Operation  and  Result.  Tie  the  thermometers  to  the  cardboard  about  an  inch  apart,  and  fasten  a 
piece  of  black  paper  over  one  bulb  and  a  piece  of  white  paper  over  the  other  bulb.  Lay  the  ap- 
paratus in  the  sunshine  and  record  the  temperature  of  each  at  frequent  intervals. 

1.  Which  color  absorbs  heat  most  readily? 

2.  What  proves  the  other  color  to  be  a  better  reflector? 

138 


RELATIVE  AMOUNTS  OF  HEAT  RECEIVED  FROM  THE  SUN 

Purpose.  To  study  the  heating  power  of  the  sun's  rays  when  they  fall  on  the  earth  at  different 
angles. 

Turn  the  binding  edge  of  a  sheet  of  cross-section  paper  toward  you,  and  let  the  heavy  line  run- 
ning parallel  with  the  lower  lengthwise  edge,  and  two  centimeters  from  it,  represent  the  earth's 
surface.  Using  your  ruler,  make  this  line  heavier,  labeling  it  "  Surface  of  the  Earth."  Near  the  left- 
hand  edge  of  your  paper  lay  your  ruler  at  a  right  angle  to  this  line  and  draw  lines  from  it  about  five 
inches  in  length  along  both  edges  of  your  ruler.  Color  the  space  between  them,  above  the  "surface" 
line,  and  label  it  "  A  Vertical  Sunbeam." 

A  short  distance  to  the  right  of  this,  again  lay  your  ruler  across  this  "surface"  line,  placing  it,  by 
means  of  a  protractor,  at  an  angle  of  66^°.  Draw  lines  along  both  edges  of  your  ruler  as  before,  and 
color  in  the  space.  Label  it  "A  Sunbeam  at  66 J°." 

At  the  right  of  this,  draw  another  sunbeam  at  an  angle  of  23£°.  Be  sure  that  both  sides  of  it  come 
to  the  "  surface  "  line.  Color  and  properly  label  it. 

Questions.  1.  Since  these  sunbeams  are  of  the  same  size,  how  does  the  amount  of  heat  in  one 
compare  with  the  amount  in  the  others? 

2.  Count  the  number  of  millimeters  each  beam  covers  in  the  line  representing  the  earth's  surface, 
and  write  the  number  in  each. 

3.  Do  these  sunbeams  spread  their  heat  over  the  same  amount  of  the  earth's  surface?    Do  they, 
therefore,  heat  the  surface  equally  ?    Explain. 


4.  When  the  sun  is  over  the  equator,  at  what  latitude  does  this  vertical  ray  strike  the  earth?    At 
what  latitude  the  sunbeam  of  66^°?    At  what  latitude  the  sunbeam  of  23|°? 

5.  Clearly  state  the  reason  why  the  average  temperature  of  the  earth's  surface  decreases  gradually 
from  the  equator  to  the  poles. 


Determine  the  angle  at  which  the  sunbeam,  at  your  locality,  falls  at  noon  on  March  21  (90°  minus 
your  latitude)  ;  on  June  21  (90°  +  23$°  -  your  latitude)  ;  and  on  Dec.  22  (90°  -  23J0  -  your  lati- 
tude). On  another  sheet  of  cross-section  paper,  draw  beams  the  width  of  your  ruler,  coming  down 
at  these  angles  to  a  line  representing  the  earth's  surface.  Color  each  space,  and  in  it  write  the  proper 
date  and  the  number  of  millimeters  it  covers  on  the  line  representing  the  earth's  surface. 

6.  Why  is  it  warmer  in  your  locality  in  June  than  in  January  ? 

7.  Explain  why  the  heat  from  the  sun  on  a  clear  day  increases  until  noon  and  then  decreases. 


140 


ELEMENTARY   EXERCISE   ON   ISOTHERMS 

Purpose.     To  map  and  to  study  the  average  annual  distribution  of  temperature  in  the  United  States. 

Directions.  On  a  blank  weather  map  of  the  United  States  (p.  193)  clearly  dot  each  city,  and 
with  neat  figures  write  the  given  temperature  on  the  north  side  of  each  dot.  To  map  the  temperature, 
lines  should  be  drawn  through  all  places  having  the  even  temperature  of  40°,  50°,  60°,  70°. 

To  connect  those  at  40°,  start  the  line  from  Chatham  on  the  Atlantic  coast,  and  draw  it  toward  the 
nearest  city  having  the  same  temperature  —  Parry  Sound.  Since  Quebec  is  at  39°  and  Montreal  at  41°, 
the  line  cannot  go  through  either,  but  must  pass  halfway  between  them.  From  Parry  Sound,  the  line 
goes  to  Marquette,  passing  south  of  Sault  Ste.  Marie,  —  one  eleventh  of  the  way  toward  Toledo,  since 
they  differ  eleven  degrees  in  temperature.  Further  west,  Duluth  is  at  38°  and  La  Crosse  is  at  46°. 
Since  they  differ  eight  degrees,  this  isotherm  of  40°  must  pass  two  eighths  of  the  way  from  Duluth  to 
La  Crosse.  In  this  way  construct  the  line  west  to  Medicine  Hat,  curving  the  line  to  avoid  any  angles. 

Then  draw  another  line  through  cities  having  a  temperature  of  50°;  another  line  through  those  at 
60° ;  and  another  through  places  at  70°.  Write  the  proper  temperature  at  both  ends  of  each  line.  Label 
the  map  :  Isothermal  Chart  of  the  United  States  for  the  Year. 

1.  Which  part  of  the  United  States  is  the  coldest?    Why  ? 

2.  How  many  degrees  does  the  temperature  change  along  the  Pacific  coast  from  Tacoma  to  San 
Diego  ?    Along  the  Atlantic  coast  from  Jupiter  to  Boston  ?    Which  varies  more  ? 

3.  Explain  the  southward  bend  of  the  50°  isotherm  in  Colorado  and  New  Mexico. 


AVERAGE  ANNUAL  TEMPERATURE  AND   RAINFALL 

Not  corrected  for  elevation  above  the  sea. 


TEMP. 
(In  Degrees^ 

RAINFALL 
(In  Inches) 

Ti.vr 
(In  Degrees  J 

K  MS  FALL 

(In  Inches'* 

TKMP. 

(In  Degrees  J 

1:  US  FALL 

(In  Inches) 

ATLANTIC  REGION 

LAKE  REGION 

ROCKY  MOUNTAINS 

Chatham 

40 

42 

Buffalo 

IS 

38 

TO  PACIFIC 

Montreal 

41 

41 

Toledo 

BQ 

31 

Phoenix 

70 

5 

Quebec 

39 

42 

Chicago 

50 

• 

Yuma 

72 

3 

Boston 

50 

43 

Parry  Sound 

40 

38 

San  Diego 

60 

11 

Albany 

48 

38 

Sault  Ste.  Marie 

26 

Sim  I.uis  Obispo 

60 

17 

New  York 

52 

45 

Marquette 

40 

32 

Independence 

60 

6 

Scran  ton 

50 

35 

Duluth 

38 

») 

San  Francisco 

56 

24 

Norfolk 

<» 

52 

S.-irramento 

(K) 

20 

Charlotte 

80 

52 

GT.  LAKES  TO  ROCKY 

Red  Bluff 

60 

26 

Atlanta 

60 

52 

MOUNTAINS 

Eureka 

.", 

46 

Jacksonville 

70 

54 

La  Crosse 

M 

30 

Reno 

60 

8 

Jupiter 

74 

61 

Moorhead 

38 

•_'4 

Winncmucca 

50 

8 

GULF  REGION 

Huron 

42 

20 

Salt  Lake  City 

52 

16 

Tampa 
Mobile 
New  Orleans 
Galveston 
Corpus  Christi 
Memphis 

72 
G8 
70 
70 
70 
61 

.-,:, 
62 

<>i 

48 
29 
53 

Bismarck 
Havre 
Medicine  Hat 
Denver 
Pueblo 
Omaha 

40 
40 
40 
49 
51 
DO 

18 
14 
14 
14 

u 

L'S 

Grand  Junction 

l'c>r:itello 

BotM 

Spokane 
Portland 
Tacoma 

50 
48 
50 
47 
53 
50 

9 
15 
14 

20 
47 
45 

Davenport 

50 

34 

OHIO  VALLEY 

Oklahoma 

60 

30 

Chattanooga 

GO 

53 

Fort  Smith 

60 

45 

Nashville 

60 

50 

Santa  Fe 

50 

14 

Cairo 

59 

43 

El  Paso 

65 

9 

Pittsburg 

52 

37 

Amarillo 

55 

20 

142 


DISTRIBUTION    OF    TEMPERATURE 

Purpose.     To  study  the  distribution  of  temperature  over  the  earth,  and  the  influences  that  affect  it. 
Material.     Isothermal  maps  of  the  world  for  January  and  July,  in  your  text-book  or  atlas. 

NOTE.    The  temperatures  reported  from  places  have  been  changed  to  show  what  they  would  be  if  all  places  were 
at  sea  level.    Hence  the  influence  of  highlands  is  not  shown. 

A.  1.   Find  the  two  or  three  areas  of  greatest  heat  on  each  map.     What  is  their  average  latitude  in 
July  ?    In  January  ? 

•2.    Why  do  the  areas  of  greatest  heat  regularly  change  to  these  different  latitudes  every  six  months? 

B.  3.   What  is  the  average  July  temperature  at  the  middle  of  North  America  (at  the  crossing  of 
the  40th  parallel  and  the  100th  meridian)  ? 

4.  What  is  the  average  July  temperature  at  the  middle  of  the  ocean  at  this  same  latitude  and 
the  crossing  of  the  160th  meridian  west  longitude  ? 

5.  Which,  therefore,  is  the  warmer  in  summer,  the  middle  of  the  continent  or  of  the  ocean  ? 

6.  What  is  the  average  January  temperature  of  each  of  these  two  places? 

7.  Which,  therefore,  is  the  cooler  in  winter  ? 

8.  Which,  therefore,  has  a  greater  range  (change)  of  temperature  annually,  an  ocean  or  a  continent? 

C.  9.    Which  hemisphere,  northern  or  southern,  has  the  greater  land  area?     Which  the  greater 
water  area?    In  which  do  the  isotherms  most  nearly  coincide  with  the  parallels  of  latitude?    Explain 
why. 

D.  10.    In  what  direction  do  the  prevailing  winds  blow  across  North  America  in  the  neighborhood 
of  the  40th  parallel  ?     In  July,  at  this  latitude,  what  is  the  temperature  at  the  shore  of  the  Pacific  ?     At 
the  shore  of  the  Atlantic ?     Although  the  oceans  near  these  two  places  have  about  the  same,  tempera- 
ture, one  place  is  much  warmer  than  the  other.     Explain  why.     Which  place  is  cooler  in  January? 
Explain  why. 

E.  11.    At  the  same  latitude,  which  place  is  warmer  in  both  January  and  July,  the  ocean  near 
England  or  near  Labrador?    The  ocean  near  Norway  or  near  Greenland?    The  Atlantic  Ocean  at  the 
Tropic  of  Capricorn  near  South  America,  or  near  Africa  ? 

12.   Consult  a  map  of  ocean  currents  and  explain  why  the  temperatures   vary  so  many  degrees  in 
each  of  the  three  cases  just  named. 

F.  13.   Review  parts  A,  B,  C,  D,  and  E,  and  state  five  influences  that  affect  the  distribution  of 
temperature  over  the  earth. 

Advanced  Questions.     14.   If  the  entire  earth's  surface   were  level  land,  how   would   the  earth's 
temperatures  be  distributed  ? 

15.  What  and  where  is  the  lowest  temperature  shown  in  these  maps  in  January?    In  July?     Why 
is  one  lower  than  the  other? 

16.  Account  for  the  crowded  isotherms  in  Alaska  in  January. 

17.  In  which  month  is  the  effect  of  the  Gulf  Stream  and  the  North  Atlantic  Drift  most  apparent  ? 
Explain  why. 

18.  What  do  these  maps  show  to  be  the  range  of  temperature  at  your  home  city?    Compare  the 
range  at  the  western  shore  of  Europe  at  the  same  latitude,  and  explain  the  difference. 


144 


SEASONAL   RANGE  OF   TEMPERATURE.     EFFECT  OF  LATITUDE 


Purpose.  To  plot  and  to  study  the  seasonal  range  of  temperature  at  several  places  located  at  the 
ocean's  shore  but  at  different  latitudes. 

Directions.  Let  the  heavy  vertical  lines  of  a  sheet  of  cross-section  paper  represent  the  months  of 
the  year  in  order.  At  the  top  of  the  left  vertical  line  write  Jan. ;  at  the  top  of  the  second  heavy  line 
write  Feb.  In  this  way,  show  the  months  given  in  the  table  below.  Number  the  end  of  the  top  hori- 
zontal line  100°.  Let  one  cm.  space  up  and  down  represent  10°.  Number  the  other  horizontal  lines  to 
the  bottom  of  the  page. 

Place  a  dot  on  the  left  vertical  line  to  show  the  temperature  recorded  in  table  I  (for  Para)  for 
Jan.  In  the  same  way  dot  the  temperature  for  each  of  the  other  months  in  this  table.  Connect  the 
dots  with  a  curving  line.  This  line  is  called  the  "  temperature  curve."  In  the  same  way,  draw  curves 
for  tables  II,  III,  IV,  and  V.  Use  lines  of  different  colors  if  desired.  Write  the  name  of  the  city  and 
its  latitude  at  the  end  of  each  curve.  Put  all  the  lines  on  the  same  sheet. 

TEMPERATURES,  IN  DEGREES  F. 


PLACE 

LAX. 

JAN. 

FEB. 

Men. 

APR. 

MAT 

JUNE 

JULY 

Auo. 

Ban. 

OCT. 

Nov. 

DEC. 

JAN. 

I. 

Para,  Brazil   .  . 

0° 

81 

79 

78 

79 

80 

81 

81 

82 

82 

82 

83 

82 

81 

II. 

Galveston,  Tex.  . 

29°  N. 

52 

58 

63 

70 

77 

82 

84 

82 

77 

71 

62 

56 

52 

III. 

Portland,  Me.  .  . 

44°  N. 

21 

22 

30 

41 

52 

63 

68 

66 

60 

48 

37 

26 

21 

IV. 

Fort  Conger  .  .  . 

82°  N. 

-38 

-40 

-28 

-14 

15 

33 

37 

34 

16 

-9 

-24 

-28 

—  38 

V. 

Buenos  Aires,  Arg. 

35°  S. 

76 

75 

72 

67 

60 

:,.-, 

51 

52 

56 

60 

IK; 

71 

76 

VI. 

Chicago,  111.   .  . 

42°  N. 

24 

25 

34 

46 

57 

66 

72 

71 

64 

53 

:;;i 

29 

24 

1.    What  month  is  warmest  in  curve  II? 
est  month  ? 


In  ci.rve  III?  IV?         Why  is  this  the  warm - 


2.    What  month  is  the  coldest  in  curve  II? 


III? 


IV? 


Why? 


3.  What  is  the  amount  of  seasonal  range  of  temperature  in  curve  I  ?         II?         III?         IV? 

4.  What  is  the  warmest   month  in  curve  V?     Coldest  mouthy     Why  is  this  curve  different  from 
the  others? 


5.  Consult  maps  showing  these  cities  and  state  whether  the  temperature  ranges  at  these  cities  vary 
because  they  are  at  different  distances  from  the  sea,  or  at  different  altitudes  above  the  sea. 

What  must  be  the  reason  for  their  difference  ? 

6.  Why  is  Fort  Conger  so  excessively  cold  from  October  until  April? 

7.  Why  does  Para  have  a  smaller  annual  range  than  the  other  cities? 

8.  Plot  the  Chicago  curve  from  the  above  data. 


146 


SEASONAL  RANGE  OF  TEMPERATURE.  EFFECT  OF  LAND  AND  SEA 

Purpose.  To  plot  and  to  study  the  seasonal  range  of  temperature  at  two  places  which  are  at  equal 
distances  from  the  equator,  and  at  equal  altitudes:  one  place  being  in  the  interior  of  a  continent  (St. 
Louis,  Mo.)  ;  the  other  place  being  on  an  island  in  the  ocean  (Ponta  Delgada,  Azores  Is.). 

Directions.  Mark  the  months  along  the  top  margin  of  a  sheet  of  cross-section  paper,  and  the  tem- 
peratures along  the  side  margin  just  as  in  the  preceding  exercise.  Draw  the  temperature  curves  for 
both  places  on  the  same  sheet. 

TEMPERATURES,  IN  DEGREES  F. 


JAN. 

FEB. 

Men. 

APR. 

M  \\ 

Jon 

JULT? 

AM.. 

SEPT. 

OCT. 

Nov. 

Dsc. 

JAN. 

I. 

St.  Louis,  Mo.  .     .     . 

30 

35 

42 

55 

65 

75 

84 

76 

69 

57 

44 

34 

30 

II. 

Ponta  Delgada  .     .     . 

66 

65 

06 

68 

70 

72 

74 

7.1 

71 

72 

(ill 

<>7 

06 

1.   State  the  latitude  and  describe  the  general  location  of  each  of  these  places. 


2.  What  is  the  amount  of  seasonal  range  (change)  of  temperature  in  curve  I  ?    In  curve  1 1 ''. 

3.  Which  of  the  two  places  shows  the  smaller  range  ?    The  greater  range  ? 

4.  Do  these  places  differ  because  they  are  at  different  latitudes  ?    At  different  altitudes  ? 

5.  What,  then,  must  be  the  reason  ? 


148 


DAILY    RANGE  OF   TEMPERATURE 

Purpose.  To  plot  and  to  study  the  daily  changes  of  temperature  in  summer  and  in  winter :  (a)  at 
a  place  in  the  interior  of  a  continent  (St.  Louis),  and  (b)  at  a  place  on  an  island  in  the  ocean  (Key  West). 

Directions.  Write,  12  Midnight  at  the  top  of  the  left  vertical  line  of  a  sheet  of  cross-section  paper. 
Let  each  of  the  centimeter  spaces  from  left  to  right  represent  two  hours.  Mark  the  proper  hour  of  A.M. 
or  P.M.  at  the  top  of  each  vertical  line  as  far  as  the  next  midnight  line.  Using  a  ruler,  make  the  noon 
and  midnight  lines  heavier,  and  label  each. 

Number  the  end  of  the  top  horizontal  line  100°  F.  Let  one  centimeter  space  up  and  down  repre- 
sent 5°.  Number  the  other  horizontal  lines  to  the  bottom  of  the  page. 

Place  a  dot  on  the  left  midnight  line  at  the  temperature  recorded  below  in  table  I.  In  the  same 
way  dot  the  temperature  for  each  of  the  other  hours  in  this  table.  Connect  these  dots  with  a  curving 
line.  This  line  is  called  the  "  temperature  curve." 

In  the  same  manner,  on  the  same  sheet,  plot  the  temperatures  shown  in  tables  II,  III,  and  IV,  and 
draw  the  curves,  numbering  the  curves  the  same  as  the  table. 

TEMPERATURES,  IN  DEGREES  F. 


MID- 
NIGHT 

2 

4 

6 

8 

10 

NOON 

2 

4 

6 

8 

10 

M  ID- 
MI.  IIT 

I. 

Key  West  (summer) 

79 

78 

77 

79 

83 

86 

88 

90 

90 

88 

83 

80 

79 

II. 

Key  West  (winter) 

68 

66 

65 

64' 

67 

73 

77 

78 

77 

75   ' 

7:? 

70 

68 

III. 

St.  Louis  (summer) 

76 

72 

69 

70 

74 

81 

91 

97 

iff 

88 

HI 

78 

re 

IV. 

St.  Louis  (winter) 

11 

10 

7 

5 

6 

12 

19 

:;•_• 

26 

20 

16 

13 

11 

1.   State  the  latitude  and  general  location  of  each  of  these  places. 


2.  What  hour  is  the  warmest  in  curve  I?        In  curve  II?         III?         IV? 

3.  Why  is  this  the  warmest  part  of  the  day  ? 

4.  What  is  the  coldest  hour  in  curve  I?        II?         III?         IV? 

5.  Why  is  this  the  coldest  part  of  the  day  ? 

6.  What  is  the  amount  of  daily  temperature  change  (range)  in  curve  I?         II?         III?         IV? 

7.  Which  of  these  two  places  shows  the  greater  range  in  summer?    In  winter? 

8.  State  two  reasons  for  this. 

Advanced  Questions.     9.   At  each  place,  does  the  temperature  begin  to  increase  at  an  earlier  hour 
in  summer  or  in  winter? 

From  the  almanacs  find  the  time  of  sunrise  in  summer  (July  1)  at  each  place. 

10.  At  which  should  the  temperature  begin  to  increase  earlier? 

11.  How  much  earlier  ? 

12.  In  the  same  way  compare  them  in  winter  (Jan.  1). 

150 


TERRESTRIAL   OR   PLANETARY   WIND   BELTS 


Purpose.     To  study  the  location  and  characteristics  of  the  wind  belts  of  the  earth. 

Material.  Two  pilot  charts  of  the  North  Atlantic  Ocean  —  a  summer  month  and  a  winter  month. 
(These  charts  may  be  obtained  from  the  Hydrographic  Office,  Washington,  D.C.) 

You  are  to  study  the  winds  in  the  middle  of  the  ocean,  away  from  the  influence  of  the  land,  and 
record  the  facts  you  learn  in  the  blank  spaces  of  the  table  below.  The  equatorial  calms  lie  in  the  south- 
ern part  of  the  chart,  bounded  by  two  dotted  lines  named  "  northern  limit  of  the  southeast  trades " 
and  "southern  limit  of  the  northeast  trades."  The  trade  belt  extends  from  the  equatorial  calms  to  a 
line  marked  "northern  limit  of  the  northeast  trades."  The  tropical  calm  belt  extends  from  the  north- 
ern border  of  the  trades  nearly  to  the  Azores  Islands.  The.prevailing  westerlies  extend  from  the  tropical 
calms  north  beyond  the  limits  of  the  chart.  In  recording  the  latitude  of  each  belt,  give  the  north  and 
the  south  boundary  in  the  middle  of  the  ocean  —  summer  month  in  one  line,  winter  month  in  the  other. 

The  character  of  the  winds  in  each  rectangle  bounded  by  the  light  black  lines  (either  continuous  or 
dashed)  is  indicated  by  the  diagram  called  a  "  wind  rose,"  in  blue  at  the  center  of  the  rectangle.  The 
figure  within  the  circle  is  the  per  cent  of  time  calm.  In  filling  the  blank  of  the  table,  give  the  highest, 
the  lowest,  and  the  average  of  several  rectangles  near  the  middle  of  the  ocean,  in  each  wind  belt. 

The  directions  of  the  winds  are  indicated  by  the  blue  lines  (arrows)  drawn  to  the  circle.  The  wind 
comes  in  the  direction  of  the  arrow  toward  the  center.  Give  as  the  prevailing  direction  that  indicated 
by  the  longest  arrow,  or  if  there  are  several  long  arrows,  give  an  intermediate  direction  between  them. 
Give  the  direction  from  which  the  wind  comes.  If  no  direction  seems  to  prevail,  write  "variable." 

The  length  of  the  arrow  shows  the  comparative  length  of  time  the  wind  blows  from  the  direction 
indicated.  Under  the  head  "  constancy  of  direction  "  in  the  table  use  adjectives,  such  as  "  very  con- 
stant," "  moderately  constant,"  "  very  irregular,"  etc.,  to  describe  the  steadiness  of  direction  of  the  wind. 

The  velocity  of  the  wind  is  shown  by  the  "feathers"  at  the  end  of  the  arrow.  The  numbers  of 
feathers  correspond  with  the  numbers  of  Beaufort's  Scale  here  given.  Record  for  each  belt  the  maximum 
velocity  indicated  and  the  most  common  velocity.  This  maximum  is  not  the  strongest  wind  experienced 
in  the  belt,  but  the  month's  average  from  the  direction  indicated. 

BEAUFORT'S  SCALE 


NUMBER 

OF 

FEATHERS 

KIND  OF  WIND 

MILES 

PER 

HOUR 

NUMBER 

OF 

FEATHERS 

KIND  OF  WIND 

MILES 

PER 

HOUR 

o 

Calm  

0     3 

7 

.Moderate  Gale 

34-40 

1 

Light  Air    .     .     .     . 

3-  8 

8 

Fresh  Gale  

40-48 

2 

Light  Breeze    

8-13 

9 

Strong  Gale      

48-56 

3 

Gentle  Breeze  

13-18 

10 

Whole  Gale      

56-65 

4 

Moderate  Breeze  

18-23 

11 

Storm      

65-75 

5 

Fresh  Breeze    

23-28 

12 

75-90 

6 

Strong  Breeze  

28-34 

and  over 

CHARACTERISTICS   OF   WIND   BELTS 


EQUATORIAL  CALMS 
OR  DOLDRUMS 

N.  E.  TRADES 

TROPICAL  CALMS, 
HORSE  LATITUDES 

PREVAILING 
WESTERLIES 

Latitude^!™-    ;   ;   ;   ; 

Per  cent  of  time  calm  .... 

Prevailing  direction  of  wind 

Constancy  of  direction     .     .     . 

TT  i     -.1.     S  Maximum  .... 
Velocity  }  Ayerage      .... 

151 


Advanced  Questions.     1.    Which  belts  are  narrow? 

2.  Which  are  wide? 

3.  In  which  belts  are  the  winds  noticeably  variable? 

4.  In  which  are  they  more  constant? 

5.  In  which  is  a  relatively  large  per  cent  of  the  time  calm  ? 

6.  In  which  is  there  little  time  calm  ? 

7.  Explain  from  the  direction  of  air  movement  why  these  things  are  so. 

8.  How  does  the  summer  month  differ  from  the  winter  month  in  velocity  of  winds,  directions,  etc.  V 


9.  On  a  blank  Mercator's  map  (from  near  end  of  this  book)  plot  the  wind  belts.  Use  arrows  to 
indicate  prevailing  directions,  —  longer  for  the  more  constant  winds  ;  use  small  circles  to  mark  the 
equatorial  calms,  and  small  crosses  for  the  tropical  calms. 


152 


FERREL'S  LAW 

Object.     To  learn  how  the  rotation  of  the  earth  affects  the  direction  of  winds  and  currents. 

Material.     A  small  globe,  a  pin,  and  a  string. 

Directions.  Put  a  pin  through  a  knot  at  one  end  of  a  string  two  feet  or  more  long.  Prick  no  holes 
in  the  globe,  but  find  several  holes  already  made  along  longitude  180°.  Put  a  pin  in  a  hole  in  the  north 
temperate  zone.  Extend  the  string  straight  north  (globe  direction)  in  a  plane  horizontal  to  the  sur- 
face of  the  globe  at  the  place  it  touches,  and  hold  it  at  the  end.  Turn  the  globe  slowly  to  the  east 
(counterclockwise)  through  less  than  £  of  a  rotation,  holding  the  end  of  the  string  all  the  time  in  the 
same  place.  The  wind  is  supposed  to  start  at  the  pin  and  blow  toward  your  hand,  to  the  north. 

1.  The  earth's  rotation  deflects  the  wind  to  the  east  or  the  west  of  a  north  direction  ? 

To  the  right,  or  to  the  left,  as  you  stand  facing  north? 

Extend  the  string  east  from  the  pin  (at  right  angles  to  the  meridian,  horizontal).  Rotate  the  globe 
slightly  to  the  east,  being  careful  to  keep  the  string  taut  by  pulling  straight  on  it. 

2.  The  west  wind,  from  the  pin  toward  the  hand,  is  deflected  to  the  north  or  to  the  south  of  east? 

To  the  right,  or  to  the  left,  of  one  facing  east  ? 

For  the  north  wind,  extend  the  string  south  from  the  pin.     Rotate  the  globe  toward  the  east. 

3.  Does  the  rotation  of  the  earth  deflect  this  wind  to  the  east,  or  to  the  west,  of  a  south  direction  ? 

To  the  right,  or  to  the  left,  of  one  going  with  the  wind  ? 

Extend  the  string  west  from  the  pin  horizontally  at  right  angles  to  the  meridian  to  represent  an  east 
wind. 

4.  Does  the  earth's  rotation  deflect  this  wind  to  the  north,  or  to  the  south,  of  a  west  direction  ? 

To  the  right,  or  to  the  left  ? 

5.  Try  the  same  experiments  at  other  latitudes  north  of  the  equator.     A  wind  in  the  northern 
hemisphere,  blowing  in  any  direction,  is  deflected  by  the  earth's  rotation  to  which  hand  ? 

Put  the  pin  in  a  hole  in  a  south  temperate  latitude,  and  slightly  rotate  the  globe  toward  the  east 
with  the  string  extended  toward  the  north,  east,  south,  and  west.  Note  the  direction  of  deflection.  Try 
other  southern  latitudes. 

6.  A  wind  in  the  southern  hemisphere,  blowing  in  any  direction,  is  deflected  by  the  earth's  rota- 
tion to  which  hand? 

Repeat  the  experiment  with  the  pin  at  the  equator. 

7.  What  result  do  you  obtain  ? 

Repeat  again  with  the  pin  near  a  pole. 

8.  Is  the  deflection  greater  near  the  equator,  or  far  from  it  ? 

Fill  the  blanks  in  this  statement  of  Ferrel's  Law. 

Bodies  moving  freely  (wind,  water,  cannon  ball)  in  any  horizontal  direction  are  deflected  by  the 

earth's  rotation  to  the hand  in  the  northern  hemisphere,  and  to  the  _  -  hand  in  the 

southern  hemisphere.  At  the  equator  the  deflection  is (much  or  little)  ;  the  farther  a  place 

is  from  the  equator  the (greater  or  less)  is  the  deflection. 


153 


WEATHER   MAPS 
Purpose.     To  represent,  on  a  map,  the  weather  conditions  on  a  given  date. 

OBSERVATIONS  TAKEN   FEB.    10,    1907,   AT  8   A.M.,   75xn   MERIDIAN  TIME 


BAROM. 

THERM. 

WIND 

DlREC- 
*  TION 

PRECIPI- 
TATION 

BAROM. 

THERM. 

WIND 
DIREC- 
TION 

PRECIPI- 
TATION 

ATLANTIC  REGION 

Miss.  RIVER  TO  THE 

Father  Point 

29.8 

15 

S. 

S. 

ROCKY  MTS. 

Halifax 

30.0 

20 

S.E. 

S. 

Moorhead 

30.2 

18 

N.W. 

Quebec 

29.7 

20 

S. 

S. 

Williston 

30.4 

12 

\V. 

Montreal 

29.6 

22 

S. 

S. 

Prince  Albert 

30.2 

12 

W. 

Rockliffe 

29.4 

26 

E. 

S. 

Edmonton 

30.2 

20 

w. 

Boston 

29.9 

20 

S. 

S. 

Medicine  Hat 

30.4 

20 

\v. 

Albany 

29.8 

20 

S. 

S. 

Helena 

30.6 

24 

w. 

Philadelphia 

29.9 

30 

S. 

s. 

Lander 

30.6 

22 

N.W. 

Norfolk 

30.0 

40 

S. 

Valentine 

30.4 

20 

N.W. 

Charleston 

30.1 

40 

w. 

Des  Moines 

30.2 

32 

N.W. 

Jupiter 

30.1 

54 

N. 

Wichita 

30.4 

30 

N. 

Pueblo 

30.5 

25 

N. 

GULF  TO  THE 

Amarillo 

30.5 

30 

N. 

GREAT  LAKES 

Abilene 

30.3 

40 

N. 

Tampa 

30.1 

46 

N. 

Mobile 

30.1 

48 

N. 

Galveston 

30.1 

50 

N.W. 

Memphis 

30.2 

44 

s.w. 

Knoxville 

30.0 

40 

s.w. 

ROCKY  MTS.  TO  THE 

Cairo 

30.2 

36 

N.W. 

PACIFIC  OCEAN 

Milwaukee 

29.8 

30 

W. 

El  Paso 

30.2 

40 

N.E. 

Columbus 

29.9 

35 

S.W. 

R. 

Santa  Fe 

30.4 

30 

N.E. 

Cleveland 

29.6 

33 

S.W. 

R. 

Phoenix 

30.1 

45 

E. 

Pittsburg 

29.8 

34 

S.W. 

R. 

Yuma 

30.1 

50 

N.E. 

Qswego 

29.6 

30 

S. 

S. 

Pocatello 

30.6 

30 

8. 

Saugeen 

29.4 

30 

s.w. 

s. 

Baker  City 

30.4 

31 

S. 

Sault  Ste.  Marie 

29.6 

25 

N. 

s. 

Roseburg 

30.2 

50 

S.E. 

Port  Arthur 

29.8 

20 

N.W. 

Portland 

30.1 

40 

S.E. 

Duluth 

30.0 

20 

N.W. 

Kamloops 

30.4 

30 

S.W. 

Directions.  A.  On  a  blank  United  States  weather  map,  plainly  dot  each  city  named  in  the 
list.  With  neat  figures,  mark  the  given  temperature  (see  the  third  column  of  the  table)  on  the  north 
side  of  each  dot.  Find  the  cities  marked  20°,  and,  beginning  at  the  Atlantic  coast,  draw  a  curving  line 
through  all  of  them.  Keep  this  isothermal  line  the  proper  distance  from  cities  having  temperatures 
slightly  above  or  below  20°  in  the  manner  explained  on  page  142.  With  another  line,  connect  the  cities 
at  30°  ;  then  those  at  40° ;  and  those  at  50°.  Mark  the  temperature  at  both  ends  of  each  of  these  lines. 

B.  On  another  blank  weather  map,  clearly  dot  the  same  cities.     On  the  north  side  of  each  dot? 
neatly  dot  the  barometer  reading  given  in  the  table.     Find  the  two  cities  marked  29.4,  and  draw 
a  free-hand  circle  connecting  them.     Then  draw  a  nearly  complete  circle  through  the  places  marked 
29.6.     Using  a  separate  line  for  each  group,  connect  places  having  the  following  pressures,  in  order  :  — 
29.8,  30.0,  30.2,  30.4,  30.6.    Print  LOW  in  the  circle  of  29.4,  and  HIGH  in  the  circle  30.6. 

Through  each  city  draw  an  arrow  one  half  inch  long,  flying  with  the  wind,  remembering  that  the 
name  of  the  wind  shows  the  direction  from  which  it  comes. 

At  the  cities  where  snow  or  rain  is  reported,  print  the  proper  letter  S.  or  R.  on  the  arrow.  Slightly 
shade  the  entire  area  where  snow  or  rain  seems  to  be  falling. 

C.  On  this  second  map  (B),  copy  the  isotherms  drawn  on  the  first  map  (A),  using  a  dotted  line  or 
a  colored  line.     Label  this  map  "  Weather  Map  for  Feb.  10,  1907." 

155 


D.  1.  Compare  the  winds  in  the  general  area  of  HIGH  pressure  (above  30.0  inches)  with  those 
fn  the  general  LOW  area,  and  describe  the  air  movement  in  each. 

L>.  Which  area  is  the  colder?  Does  the  air  seem  to  be  moving  towards  the  center  of  this  area  or 
away  from  it?  Then  is  the  air  at  this  center  sinking  or  rising? 

3.  In  which  of  these  areas  is  there  a  fall  of  snow  and  rain  ?  Does  this  indicate  rising  or  sinking  air  ? 

4.  Why  does  one  part  of  this  area  have  rain  and  the  other  have  snow? 
From  which  of  these  areas  does  the  air  move  to  the  other  ?     Why  does  it  ? 

In  the  manner  described  in  A  and  B,  draw  the  weather  map  for  Feb.  11,  from  the  data  below. 


5. 
E. 

6.  Describe  the  air  movement  around  the  LOW  and  around  the  HIGH. 

7.  How  do  these  directions  compare  with  those  of  the  previous  day  ? 


8.  Compare  the  temperature  and  snowfall  of  the  LOW  with  those  of  the  previous  day. 

9.  In  what  direction  has  the  LOW  moved  from  the  previous  day  ?    How  far  (use  scale  of  miles)  ? 
Which  way  and  how  far  has  the  HIGH  moved? 

10.  Which  of  these  areas  brings  the  cold  wave  ? 

OBSERVATIONS  TAKEN  FEB.  11,  1907,  AT  8  A.M.,  75xH  MERIDIAN  TIME 


WIND 

SNOW 

WIND 

SNOW 

FEB.  11,  1907 

BAROM. 

THERM. 

DIREC- 

OR 

BAROM. 

THERM. 

DIREC- 

OR 

TION 

RAIN 

TION 

RAIN 

ATLANTIC  REGION 

Miss.  RIVER  TO  THE 

Father  Point 

29.4 

30 

S.E. 

S. 

ROCKY  MTS. 

Halifax 

2<>.<> 

40 

S.W. 

R. 

Moorhead 

30.1 

10 

8.E. 

Quebec 

29.4 

20 

W. 

S. 

Williston 

30.0 

20 

S.W. 

Montreal 

29.6 

10 

w. 

S. 

Prince  Albert 

1SI.S 

30 

8. 

S. 

Rockliffe 

29.8 

-10 

W. 

S. 

Edmonton 

•_".».* 

:;•_• 

N. 

S. 

Boston 

29.6 

40 

w. 

s. 

Medicine  Hat 

30.0 

80 

S.W. 

S. 

Albany 

29.7 

20 

w. 

s. 

Helena 

30.4 

20 

\v. 

Philadelphia 

29.9 

30 

N.W. 

Lander 

8O6 

20 

s.\v. 

Norfolk 

29.9 

40 

N.W. 

Valentine 

30.2 

20 

\v. 

Charleston 

30.0 

50 

N.W. 

Des  Moines 

30.3 

30 

S. 

Jupiter 

30.1 

62 

N. 

Wichita 

30.4 

30 

W. 

Pueblo 

30.6 

20 

N.W. 

GULF  TO  THE 

GREAT    LAKES 

Amarillo 

Abilene 

30.5 
30.5 

30 

40 

N.W. 
N.W. 

Tampa 

30.1 

60 

N. 

Mobile 

30.2 

50 

N.W. 

ROCKY  MTS.  TO  THE 

Galveston 

30.3 

50 

•N. 

PACIFIC  OCEAN 

Memphis 

30.3 

40 

N. 

El  Paso 

30.4 

40 

E. 

Knoxville 

30.2 

30 

N.W. 

Santa  Fe 

30.5 

30 

N.K. 

Cairo 

30.3 

35 

N.W. 

Phoenix 

30.2 

50 

N.K. 

Milwaukee 

30.3 

io 

W. 

Yuma 

30.1 

:,.-, 

N.E. 

Columbus 

30.1 

25 

N.W. 

Pocatello 

90.4 

25 

S.K. 

Cleveland 

30.0 

20 

W. 

s. 

Baker  City 

:;«•.;; 

30 

Pittsburg 

30.0 

20 

W. 

Rosehmx' 

30.2 

40 

E. 

Oswego 

29.8 

14 

N.W. 

s. 

Portland 

80J 

40 

S.K. 

Saugeen 

30.0 

0 

N.W. 

s. 

Kamloops 

30.2 

• 

w. 

Sault  Ste.  Marie 

30.2 

-10 

W. 

s. 

Port  Arthur 

30.2 

-10 

s. 

Duluth 

30.2 

0 

S.K. 

156 


WEATHER    RECORD 


DATE 

BAROMETRIC 
PRESSURE 

TEMPERATURE 

RELATIVE 
HUMIDITY 

KINDS  OF 
CLOUDS 

1 
fc 

cc 
a 
o 

ta 

M 

a 

H 

AMOUNT 

DIRECTION  OF 
WIND 

POSITION  OF 
STORM  CENTER 

157 


WEATHER    RECORD 


DATE 

BAROMETRIC 
PRESSURE 

TEMPERATURE 

RELATIVE 
HUMIDITY 

KINDS  OF 
CLOUDS 

£ 

o 
M 

02 

X 
5 

H 

AMOUNT 

DIRECTION  OF 

\VlM) 

POSITION  OF 

STOIIM  <  'I:\TI  i: 

158 


THE  TEMPERATE  LATITUDE  CYCLONE 

Purpose.  To  study  the  cyclonic  storms  of  the  United  States,  which  cause  the  irregular  changes  of 
weather. 

Material.  A  group  of  daily  United  States  weather  maps  for  two  weeks  or  a  month,  bound  to- 
gether ;  a  sheet  of  tracing  paper. 

The  weather  map  is  made  from  data  telegraphed  from  all  weather  stations  to  central  stations 
—  Washington,  Chicago,  etc.  —  at  the  same  hour  in  the  morning — 8  o'clock  Eastern  time,  7  o'clock 
Central  time,  6  o'clock  Mountain  time,  5  o'clock  Pacific  time.  On  the  map  the  isotherms  are 
dotted  lines  (red  on  the  maps  printed  at  Washington);  the  isobars  are  continuous  lines;  the  areas 
marked  LOW  are  the  storm  or  cyclone  centers;  the  areas  marked  HIGH  are  the  anticyclones.  For  fur- 
ther explanation  see  the  lower  left  corner  of  the  map. 

A.  Size  of  the  Temperate  Latitude  Cyclone.  By  means  of  the  scale  of  miles  given  on  the  map 
measure  the  width  of  several  cyclonic  storms,  including  in  each  storm  all  the  isobars  that  encircle  it. 

1.   State  the  maximum,  the  minimum,  and  the  average  width. 


If  the  storm  is  oval  in  shape,  give  the  direction  of  the  longest  diameter  in  each  of  several  storms. 

B.  Direction  of  Wind  in  the  Cyclone  and  the  Anticyclone.     The  winds  represented  at  a  city  any  day 
may  be  influenced  by  local  conditions  and  so  changed  from  their  typical  direction.     That  you  may  get 
at  once  a  view  of  the  winds  of  several  storms,  and  in  this  way  overcome  the  influences  of  local  con- 
ditions, follow  these  directions  for  the  use  of  tracing  paper. 

At  the  top  of  the  sheet  of  tracing  paper  write  this  heading :  "  Tracings  from  weather  maps."  Draw 
a  vertical  line  dividing  the  page  into  two  equal  columns.  Draw  two  lines  across,  dividing  each  column 
into  three  equal  parts.  At  the  top  of  the  first  part,  on  the  middle  line  write  the  word  "  Wind,"  at  the 
top  of  the  second  part  the  word  "  Temperature,"  at  the  top  of  the  third  part  the  word  "  Moisture."  In 
the  middle  of  each  of  the  three  left-hand  sections  write  the  word  "  LOW  " ;  in  the  middle  of  each  right- 
hand  section  write  the  word  "  HIGH."  Prepare  a  sheet  of  writing  paper  in  the  same  way,  except  the 
general  heading,  which  should  be  "  Generalized  Weather  Conditions." 

Place  the  word  LOW  of  the  wind  section  of  the  tracing  paper  over  the  center  of  a  well-defined  storm 
(LOW)  on  the  weather  map  (a  storm  having  several  isobars  encircling  the  center),  the  top  of  your  paper 
to  the  north  of  the  map.  Trace  all  the  arrows  covered  by  this  section  of  your  tracing  paper.  Find  on 
any  day  another  well-defined  storm ;  place  the  same  LOW  of  your  paper  over  its  center,  top  of  your  paper 
to  the  north,  and  trace  the  arrows  here  covered. 

Repeat  the  process  till  the  arrows  of  your  tracing  paper  clearly  show  on  each  side  of  the  LOW  a  well- 
marked  prevailing  direction  of  the  wind.  In  the  corresponding  section  of  your  writing  paper  draw  six 
or  eight  arrows,  one  each  side  of  the  LOW,  each  representing  the  prevailing  direction  of  the  winds  on  its 
side  of  the  storm  as  you  observe  it  on  your  tracing  paper. 

2.  Do  the  winds  blow  toward,  or  from,  the  LOW  ?    To  which  hand  are  they  deflected  ? 

Is  this  according  to  Ferrel's  Law  ? 

Place  the  HIGH  of  the  wind  section  of  your  tracing  paper  over  a  well-defined  anticyclone  (HIGH) 
and  trace  the  arrows.  When  you  have  traced  the  arrows  of  a  sufficient  number  of  anticyclones,  draw  an 
arrow  on  each  side  of  the  word  HIGH  on  the  writing  paper  to  indicate  the  directions  of  the  wind 
around  HIGH. 

3.  Do  the  winds  blow  toward,  or  from,  the  HIGH  ?    To  which  hand  are  they  deflected  ? 

Does  this  accord  with  Ferrel's  Law? 

C.  Temperatures  of  the  Cyclones  and  the  Anticyclones.     The  temperature  of  the  storm  can  be  told 
by  means  of  isothermal  lines  in  or  near  the  center.    Note  the  temperatures  of  all  the  LOWS  in  the 

159 


central  part  of  the  United  States  during  the  few  weeks  represented  by  your  maps;  get  the  average. 
Note  the  temperatures  of  the  HIGHS  in  the  same  region,  during  the  same  time,  and  get  the  average. 

Place  the  LOW  of  the  second  section  of  your  tracing  paper  over  a  well-defined  storm  center  and 
trace  the  isotherms  covered.  Repeat  with  other  storms  till  your  paper  shows  a  prevailing  form  of 
isothermal  lines  in  or  near  the  storm.  Draw  a  single  line  through  the  corresponding  LOW  of  your 
writing  paper  to  show  this  prevailing  form.  Mark  at  the  ends  of  this  line  the  average  temperature  of 
these  LOWS.  Trace  and  record  the  isotherms  of  the  HIGH  in  the  same  way. 

4.  Which  has  the  higher  temperature,  the  cyclone  or  the  anticyclone? 

Is  the  east  side  of  the  cyclone  warmer  or  cooler  than  the  west? 

D.  Moisture  in  the  Cyclone  and  the  Anticyclone.     Place  the  LOW  of  the  third  section  of  your  tracing 
paper  over  the  center  of  a  well-defined  storm,  and  trace  the  circles  indicating  moisture  conditions,  shad- 
ing those  that  are  shaded  and  also  those  marked  R  and  5.     Repeat  for  several  storms.     Shade  the  cor- 
responding section  of  the  writing  paper  to  express  the  degree  of  cloudiness  in  different  parts  of  the  LOW. 
Study  the  HIGH  in  the  same  manner. 

5.  Is  the  LOW  generally  cloudy  or  clear  ? 

Is  the  HIGH  generally  cloudy  or  clear  ? 

On  which  side  of  the  storm  center  is  the  cloudiness  the  heaviest? 

E.  Path  of  the  Storm.     On  several  consecutive  weather  maps  find  the  same  well-defined  storm. 
On  a  blank  weather  map  write  the  day  of  the  month  on  which  the  storm  is  first  noted,  at  the  city 
nearest  the  storm  center.     On  the  same  blank  map  write  the  next  day  of  the  month  at  the  city  nearest 
the  storm  center  on  the  second  day  the  storm  is  observed ;  continue  as  long  as  the  storm  can  be  traced. 
Draw  a  line  of  arrows  connecting  these  date  figures ;  it  will  indicate  the  path  of  the  storm.     On  the 
same  blank  map  trace  the  movements  of  several  storms. 

6.  What  is  the  general  direction  of  movement  of  the  storms? 

What  is  the  greatest  number  of  miles  a  storm  moves  in  one  day  ? 

What  is  the  least  number  ? 

What  is  the  average  of  several  days  of  ordinary  movement  ? 

Advanced  Questions.     7.   Study  the  paths  of  the  anticyclones  as  you  have  those  of  the  cyclones. 
8.    Trace  the  paths  of  many  storms,  till  you  can  observe  several  routes  across  the  United  States 
commonly  taken  by  the  storms.     Describe  each  route.     Compare  summer  routes  with  winter  rout 


160 


RAINFALL    IN    THE    UNITED    STATES 

Purpose.     To  map  and  to  study  the  average  annual  rainfall  within  the  United  States. 
Directions.     On  a  blank  weather  map  of  the  United  States,  clearly  dot  each  city  named  in  the  table 
on  page  111'. 

With  neat  figures,  mark  the  number  of  inches  of  rainfall  (given  in  that  table)  on  the  north  side  of 
each  dot.     Draw  a  line  through  the  places  in  central  United  States  which  have  20  inches  of  rainfall 
(this  will  lie  in  the  neighborhood  of  the  100th  meridian).     Keep  the  line  the  proper  distance  from  the 
cities  having  other  amounts  (in  the  manner  described  on  page  142).     Then  in  order  eastward,  connect 
places  having  a  rainfall  of  30  inches,  of  40  inches,  of  50  inches,  and  of  60  inches,  respectively.     Then 
west  of  the  100th  meridian,  connect  places  having  10  inches,  20  inches,  30  inches,  and  40  inches  of  rain- 
fall.    Label  the  map  "  Average  Annual  Rainfall  of  the  United  States,  in  Inches." 
Color  lightly  the  area  between    0  inches  and  10  inches,  —  reddish  yellow ; 
"         "  "  "        10  inches  and  20  inches,  —  yellow; 

"         "  "  "        20  inches  and  40  inches,  —  light  green ; 

"          "  "  "        40  inches  and  60  inches,  —  dark  green ; 

"         "  "  above  60  inches,  —  black. 

1.   Explain  the  rainfall  of  the  following  areas,  stating  whether  it  is  mainly  due  to  its  nearness  to  or 
distance  from  the  sea,  the  direction  of  the  wind  belt,  mountains  aiding  or  hindering,  cyclonic  storms,  etc. 
(a)    Western  Oregon  and  Washington. 


(6)    Southern  Arizona. 


(c)  Northern  Nevada  and  Utah. 


(d)  The  Great  Plains. 


(e)   The  regular  increase  from  the  Great  Plains  to  the  Atlantic. 


(/)    Southeastern  Florida. 


2.  Where  must  there  be  small  areas  of  heavy  rainfall  not  indicated  by  the  reports  from  the  cities 
in  the  table? 

3.  Compare  your  map  with  the  one  on  page  8  and  be  prepared  for  an  oral  explanation  of  minor 
differences. 


162 


SEASONAL   DISTRIBUTION   OF   RAINFALL 

Purpose.  To  plot  and  to  study  the  amount  and  distribution  of  rainfall  throughout  the  year  at 
different  latitudes. 

Directions.  By  heavy  horizontal  lines,  divide  a  sheet  of  cross-section  paper  into  three  equal  parts 
(each  8  by  18  cm.).  Mark  the  base  line  of  each  of  the  three  parts,  0.  Let  one  centimeter  vertically 
represent  one  inch  of  depth  of  rainfall,  each  part  of  the  paper  thus  representing  eight  inches.  Begin- 
ning with  each  0  line,  number  the  eight  inches  of  each  section  on  the  side  margins. 

Let  the  left-hand- vertical  space,  one  centimeter  wide,  from  the  top  to  the  bottom  of  the  paper, 
represent  January.  Let  the  next  vertical  space  represent  February,  etc.,  as  given  in  the  table  below. 
Write  the  name  of  each  month  at  the  top  of  the  proper  space. 

Let  the  upper  third  of  the  sheet  represent  San  Francisco.  Across  the  space  for  January  draw  a 
horizontal  line  to  show  the  exact  depth  of  rainfall  given  in  the  table  below,  and  lightly  shade  the  space 
between  this  line  and  the  base  line.  Repeat  this  for  each  month.  In  the  same  manner  draw  the  rain- 
fall chart  for  Quito  in  the  middle  section,  and  for  Valparaiso  in  the  lower.  Write  the  name  of  the 
proper  city  in  each  section. 

RAINFALL,  IN  INCHES 


TOTAL 

PLACE 

LAT. 

JAN. 

FEB. 

MAR. 

APR. 

MAY 

JUKE 

Jri.y 

AIL. 

SF.PT. 

<i,  i. 

HOT, 

DEC. 

JAN. 

FOR 

YEAR 

San  Francisco,  Cal. 

5.6 

4.1 

8.5 

2.5 

1.2 

0.8  . 

0.1 

0.1 

0.5 

1.4 

8.8 

6.7 

5.6 

Quito,  Ecuador 

3.3 

4.0 

4.3 

7.2 

5.2 

1.8 

IJ 

•J  'J 

2.8 

4.11 

1  •_' 

86 

8.8 

Valparaiso,  Chile 

0.1 

0.2 

1.0 

1.6 

8.0 

4.1 

2.9 

1.8 

0.8 

o.:, 

0.1 

0.1 

Questions.     1.   What  months  mark  the  height  of  the  two  rainy  seasons  at  Quito? 
What  months  mark  the  dry  seasons  there  ? 

2.  What  wind  belt  near  the  equator  causes  these  heavy  rains?    Why  does  it? 

3.  Why  do  not  the  equatorial  calms  affect  Quito  every  month? 

4.  At  what  two  dates  is  the  sun  directly  over  Quito  ? 

Dot  these  dates  on  your  chart,  and  neatly  label  them  "  sun  overhead." 

5.  Does  your  chart  show  that  the  equatorial  calms  precede  or  lag  behind  the  sun  in  its  north  and 
south  movement? 

6.  In  which   months  do  the  winds  bring  the  most   rainfall  from  the  ocean  to  San  Francisco? 
In  which  direction  must  these  winds  blow?    To  what  wind  belt  must  these  winds  belong? 

7.  Which  month  shows  the  least  rainfall  in  San  Francisco?    Which  way  must  the  wind  be  blow- 
ing ?     To  what  wind  belt  must  these  winds  belong? 

8.  What  wind  belt  does  your  chart  show  must  affect  Valparaiso  in  July?    In  January '! 

9.  Why  does  Valparaiso  have  its  heavy  rains  while  San  Francisco  is  having  its  dry  season  ?. 


SEASONAL  DISTRIBUTION  OF  RAINFALL   (Advanced) 


Select  some  of  the  cities  given  in  the  following  table,  and  chart  their  rainfall  as  in  the  preceding 
exercise  or  by  means  of  curves.  To  draw  the  curves,  place  the  names  of  the  months  in  order  at  the  top 
of  the  heavy  vertical  lines.  Let  each  centimeter  vertically  represent  one  inch.  Label  the  lowest  horizontal 
line  zero,  then  write  the  proper  numbers  along  the  side  margins  to  the  top  of  the  page.  Place  a  dot  on 
each  vertical  line  at  the  proper  place  to  show  the  depth  of  rainfall  for  that  month,  and  connect  these 
dots  by  a  curving  line.  Several  curves  may  be  placed  on  the  same  page.  State  the  city  and  its  latitude 
at  the  end  of  the  curve.  If  the  curves  cross  each  other,  use  different  colors. 

RAINFALL,  IN  INCHES 


PLACE 

LAT. 

JAN. 

FEB. 

MAR. 

APR. 

MAT 

•Jr.NE 

JULY 

Auo. 

SEPT. 

OCT. 

Nov. 

DEO. 

JAN. 

TOTAL  KOH 
12  MONTHS 

Rio  Janeiro,  Brazil     .     .     . 

5.4 

5.7 

5.9 

5.4 

4.6 

1.5 

1.8 

2.8 

8.8 

8.9 

4.5 

5.1 

ft.4 

Libreville,  French  Kongo  . 

7.5 

9.0 

15.0 

10.0 

8.7 

0.9 

0.5 

1.2 

8.1 

19.4 

19.1 

7.8 

7.5 

Cape  Town,  Cape  Colony  . 

.07 

0.8 

1.0 

1.8 

4.0 

4.6 

::.,; 

3.4 

2.2 

1.8 

1.1 

0.9 

0.1 

Calicut,  India             .     .    . 

1.0 

0.8 

2  2 

4.8 

12.2 

80.0 

22.0 

14.0 

18.0 

12.2 

5.4 

1.8 

1  it 

London,  England  .... 

2.0 

1.6 

1.4 

1.8 

1.9 

2.0 

2.5 

2.4 

2.4 

2.5 

•J.I 

2.1 

2.0 

Yuma,  Arizona      .... 

0.51 

0.51 

0.26 

0.07 

0.04 

0.01 

0.14 

0.85 

0.14 

0.28 

0.29 

0.46 

0.51 

Tatoosh  Island, 

Puget  Sound 

18.6 

9.6 

9.0 

6.8 

4.6 

8.8 

1.9 

2.5 

5.6 

7.4 

18.5 

15.8 

18.6 

Chicago,  Illinois     .... 

2.0 

2.8 

2.6 

2.7 

8.5 

8.6 

:;.: 

2.9 

8.0 

2.5 

•.'.4 

2.1 

•-Mi 

Properly  fill  out  this  table  about  each  city  you  chart. 


CITY 

LAT. 

ON  A  NORTH, 
SOUTH,  EAST, 
OR  WEST 
COAST 

WIND  BKLT 

DURING 

RAINY 

SEASON 

DIRECTION  OF 
AIR  MOVEMENT 

WIND  BKLT 

|.|  I:IN.. 

DRT 

SEASON 

DIRECTION  or 
AIR  MOVEMENT 

ANT  SPECIAL  CAI>I 
MOUNTAINS,  PLAIN-. 
WAK.M  OCKAN  CUB- 

1:1  \  i  - 

1 

166 


MAGNETISM.     THE   COMPASS 

Purpose.     To  observe  magnetic  attraction,  polarity,  and  its  application  to  the  compass. 

Material.  Two  bar  magnets,  iron  filings,  or  magnetic  iron  ore  in  small  grains,  pieces  of  thread 
(some  very  fine),  and  needles. 

A.  Put  a  small  heap  (  one  fourth  teaspoonful)  of  iron  filings  or  grains  of  magnetic  iron  ore  on 
a  sheet  of  paper.  Bring  one  end  of  a  bar  magnet  within  one  half  inch  of  the  grains  of  iron.  Tap 
the  paper  gently  to  aid  the  movement  of  the  grains. 

1.   Describe  (sketch  if  you  can)  the  way  in  which  the  grains  arrange  themselves. 


2.  Bring  the  other  end  of  the  magnet  near  the  grains.     What  is  the  effect  ? 

3.  Lay  the  magnet  under  the  paper  and  sprinkle  the  grains  over  the  paper ;  tap  a  few  times  very 
gently.     Describe  (sketch)  the  arrangement  of  the  grains. 

B.  Suspend   the  magnet  in  a  sling  (a  paper  loop  at  the  end  of  a  thread).      Very  slowly  bring 
the  S  end  of  another  magnet  near  and  at  the  side  of  the  S  end  of  the  suspended  magnet. 

4.  What  motion  of  the  suspended  magnet  follows? 

Does  this  mean  attraction  or  repulsion  ? 

Bring  the  N  end  of  the  second  magnet  near  the  S  end  of  the  suspended  magnet. 

5.  What  motion  of  the  suspended  magnet  follows? 

Does  this  mean  attraction  or  repulsion  ? 

6.  Bring  the  two  .ZV  ends  near  each  other ;  what  motion  follows  ? 
Is  there  attraction  or  repulsion? 

7.  Fill  the  blanks  in  the  following  statement  by  the  correct  word  —  attract  or  repel. 

Like  poles  of  a  magnet  each  other ;  unlike  poles  each  other. 

C.  Magnetize   a   needle   by  laying   it   lengthwise  on  a  magnet  and   sliding  it   back  and   forth. 
Suspend  the  magnetized  needle  over  the  end  of  your  desk,  the  needle  horizontal,  at  the  end  of  a  long, 
very  fine  thread,  no  magnet  near.     Turn  it  back  and  forth,  then  let  it  come  to  rest. 

Repeat  this  three  or  four  times.     If  your  experiment  is  successful,  the  needle  will  repeatedly  take 
the  same  position. 

8.  Toward  what  points  of  the  compass  do  the  ends  lie  ? 

Why  do  you  think  the  needle  does  not  take  this  position  by  chance  ? 

Slowly  bring  the  N  end  of  a  magnet  near  the  north-pointing  end  of  the  needle. 

9.  Is  there  attraction  or  repulsion  shown  ? 

Does  the  N  or  the  S  end  of  the  needle  point  north  ? 

10.  Is  this  needle  a  compass? 

11.  Test  the  magnet  by  carefully  suspending  it  on  a  thread  as  long  and  as  fine  as  is  convenient,  and 
holding  it  till  it  comes  to  rest.     Try  several  times.     Is  the  large  suspended  magnet  a  compass  ? 

167 


SECTION  OF   OCEAN  BORDER.     CONTINENTAL  SHELF 

Purpose.  To  show  the  widths  of  the  continental  shelf,  the  depths  of  water,  and  the  slopes  of  the 
bottom. 

Directions.  Write  "  sea  level "  on  the  second  line  from  the  top  of  a  sheet  of  cross-section  paper.  Let 
each  centimeter  along  this  line  represent  10  miles,  and  each  centimeter  down  from  this  line  represent 
100  fathoms. 

1.    This  gives  how  much  vertical  exaggeration  ? 

Below  the  sea-level  line  make  a  series  of  small  dots  according  to  the  data  given  below.  E.g.,  for 
Atlantic  City,  one  centimeter  from  the  starting  point  (10  miles)  make  a  dot  a  little  more  than  half  a 
small  square  (12  fathoms)  below  sea  level.  Two  centimeters  (20  miles)  from  the  starting  point,  make  a 
dot  I  of  a  small  square  below  sea  level  (15  fathoms),  at  three  centimeters  (30  miles)  make  a  dot  1 J  small 
squares  (25  fathoms)  below  sea  level,  and  so  on. 

A  line  connecting  the  dots  represents  the  continental  shelf,  and  the  beginning  of  the  slope  down  to 
the  deep  sea  bottom. 

In  the  same  manner  draw  other  sections  to  the  same  sea-level  line,  using  a  different  kind  of  line  — 
dots,  dashes,  or  colors  for  each  section ;  or  draw  each  section  to  a  separate  sea-level  line. 

EAST  FROM  ATLANTIC  CITY,  N.J. 


DISTANCE 

DEPTH  OF 

DISTANCE 

DEPTH  OF 

DISTANCE 

DEPTH  OF 

FROM  SHORE, 

WATER, 

FROM  SHORE, 

WATER, 

FROM  SHORE, 

WAT  Kit, 

MILES 

FATHOMS 

MILES 

FATHOMS 

MILES 

FATHOMS 

10 

12 

50 

30 

85 

•   500 

20 

15 

60 

40 

90 

1000 

30 

25 

70 

50 

100 

1300 

40 

20 

75 

100 

2.  At  about  what  depth  does  the  steep  slope  of  the  front  of  continental  shelf  begin? 

3.  About  how  many  miles  wide  is  the  shelf  at  Atlantic  City  ? 

4.  Does  the  bottom  of  the  water  slope  continuously  down  from  the  shore  outward  ? 

FROM  JUPITER  INLET,  FLORIDA,  EAST  TO  BAHAMA  ISLANDS. 


DISTANCE 

DEPTH  OF 

DISTANCE 

DEPTH  OF 

DISTANCE 

DEPTH  OF 

FROM  SHORE, 

WATER, 

FROM  SHORK, 

WATER, 

FROM  SHORE, 

WATER, 

MILES 

FATHOMS 

MILES 

FATHOMS 

MILES 

FATHOMS 

2 

6 

30 

400 

55 

1>SO 

4 

16 

35 

430 

57 

100 

10 

100 

40 

420 

58 

0 

20 

250 

50 

340 

The  Gulf  Stream  flows  north  through  this  strait,  most  swiftly  where  the  water  is  deepest. 

5.  Which  side  of  the  strait  has  the  steeper  slope  ? 

6.  Is  the  shallow  water  bordering  the  shore  a  broader,  or  a  narrower,  strip  than  at  Atlantic  City  ? 


169 


FROM  SOUTH  PASS  (Mourn  OF  MISSISSIPPI  RIVER)  SOUTHEAST 


DISTANCE 
FROM  SHORE, 
MILKS 

DEPTH  OF 
WATER, 
FATHOMS 

DISTANCE 
FROM  SHORE, 
MILES 

DEPTH  OF 

WATER, 

FATHOMS 

DISTANCE 
FROM  SHORE, 
MILES 

DEPTH  OF 

\Y  \TER, 

FATHOMS 

2 

20 

20 

300 

40 

700 

4 

45 

25 

400 

50 

950 

10 

85 

30 

550 

15 

190 

35 

620 

7.   The  delta  at  the  mouth  of  the  Mississippi  is  building  on  this  shelf.     It  has  reached  within  how 
many  miles  of  the  border  of  the  shelf? 


For  the  section  from  Portland,  the  sea-level  line  must  run  lengthwise  of  the  paper. 

FROM  PORTLAND,  ME.,  SOUTHEAST 


DISTANCE 
FROM  SHORE, 
MILES 

DEPTH  OF 
WATER, 
FATHOMS 

DISTANCE 
FROM  SHORE, 
MILES 

DEPTH  OF 
WATKR, 
FATHOMS 

DISTANCE 
FROM  SHORE, 
MILES 

DEPTH  OF 
WATER, 
FATHOMS 

2 

20 

90 

130 

170 

25 

6 

50 

100 

110 

180 

30 

10 

75 

110 

90 

190 

35 

20 

100 

120 

100 

200 

45 

30 

50 

130 

105 

210 

55 

40 

70 

140 

20 

220 

70 

50 

90 

142 

10 

225 

100 

60 

50 

146 

20 

230 

500 

70 

100 

150 

20 

235 

1000 

80 

110 

160 

20 

240 

1300 

8.  The  shallow  strip  beginning  140  miles  from  shore  is  probably  a  glacial  moraine.     It  is  valuable 
as  a  fishing  bank.     How  wide  is  this  bank  ? 

9.  How  many  miles  wide  is  the  shelf  at  Portland  ? 

10.  Is  the  bottom  more,  or  less,  uneven  than  in  the  Atlantic  City  section  ? 


170 


SECTION   OF   THE    NORTH    ATLANTIC   OCEAN 

Purpose.  To  draw  a  profile  from  the  Blue  Ridge  Mountains,  Virginia,  to  Monte  Junto,  Portugal, 
showing  the  slopes  of  the  land  and  the  depths  of  the  ocean,  at  latitude  39°  N. 

Directions.  On  a  sheet  of  cross-section  paper,  draw  a  line  parallel  to  the  binding  margin  of 
the  paper  and  three  centimeters  from  the  margin,  and  label  it  "sea  level."  Using  a  horizontal 
scale  of  one  centimeter  for  200  miles,  and  a  vertical  scale  of  one  centimeter  for  1000  fathoms 
(=  6000  feet),  make  a  series  of  dots  according  to  the  following  data  and  draw  line  connecting  the 
dots.  Shade  green  or  blue  the  space  between  sea  level  and  the  bottom  of  the  ocean. 


DISTANCE  FROM  WEST  END 


0  miles,  Blue  •  Ridge 
10  miles,  foot  of  mountain 

200  miles,  shore 

290  miles,  shelf 

320  miles, 

540  miles, 
1000  miles, 
1640  miles, 
2260  miles, 
2460  miles, 

2660  miles,  edge  of  ridge 
2685  miles,  shore  Azores  Islands 
2700  miles,  edge  of  ridge 
2800  miles, 
2940  miles, 
3560  miles, 
3610  miles, 
3640  miles,  shore 
3665  miles,  Monte  Junto 


LAND  SURFACE  OR  OCEAN  BOTTOM 


3000  feet  altitude 

1000  feet  altitude 

0  feet  altitude 

100  fathoms  'deep 
1000  fathoms  deep 
2000  fathoms  deep 
3000  fathoms  deep 
3000  fathoms  deep 
2000  fathoms  deep 
1000  fathoms  deep 

500  fathoms  deep 
0  feet  altitude 

500  fathoms  deep 
1000  fathoms  deep 
2000  fathoms  deep 
2000  fathoms  deep 

500  fathoms  deep 

0  feet  altitude 
2200  feet  altitude 


About  1200  miles  from  the  west  side  of  the  ocean,  write  at  the  proper  places  for  the  depths 
here  given,  the  temperatures  of  the  water.  At  the  surface  70  degrees,  at  a  depth  of  200  fathoms 
39  degrees,  at  a  depth  of  1000  fathoms  38  degrees,  at  the  bottom  35  degrees. 

Questions.     1.   How  much  is  the  vertical  exaggeration  of  the  section  ? 

2.  About  how  many  miles  wide  is  the  Atlantic  Ocean  at  latitude  39°  N  ?     How  deep  ?     Where 
is  the  deeper  part? 

3.  How  broad  is  the  ridge  on  which  the  Azores  Islands  stand? 

4.  Which  side  of  the  ocean  at  this  latitude  has  the  broader  continental  shelf?    Which  has  the 
broader  coastal  plain? 

5.  Do  you  think  the  seashore,  or  the  edge  of  the  continental  shelf,  should  be  taken  as  the  border  of 
the  continent?     Give  a  reason. 

6.  Does  the  temperature  change  more  rapidly  near  the  surface,  or  near  the  bottom,  of  the  ocean  ? 


172 


TIDES   IN    THE    OCEAN 


Purpose.     To  study  the  tidal  changes  of  water  level. 

According  to  the  following  directions  make  a  graph  to  represent  the  upward  and  downward 
movements  of  the  surface  of  the  sea  at  Eastport,  Maine,  from  Sept.  17  to  Sept.  28,  1899. 

On  a  sheet  of  cross-section  paper,  along  the  binding  border,  write  numbers  on  heavy  lines  to 
represent  the  days  of  the  month  given  above;  —  thus,  one  centimeter  from  the  left  write  17,  three 
centimeters  from  the  left  18,  five  centimeters  19,  etc.,  two  centimeters  representing  one  day,  and  the 
number  being  written  on  the  noon  line.  Notice  that  6  o'clock  will  come  in  the  middle  of  the  centi- 
meter space ;  estimate  the  positions  of  the  other  hours.  Four  centimeters  from  the  top  draw  a  line 
across  the  sheet  and  label  it  "  mean  (average)  sea  level."  At  the  ends  label  the  heavy  lines  above  mean 
sea  level  5,  10,  15,  and  the  heavy  lines  below  —  5,  —  10,  —  15,  each  centimeter  representing  five  feet. 

Make  a  dot  in  the  proper  place  for  2:21  A.M.  (about  one  small  square  from  the  left)  and 
-  10.3  feet,  —  the  first  ebb  tide  Sept.  17.  Make  another  dot  for  8:28  A.M.  (more  than  three  small 
squares  from  the  left)  and  9.8  feet,  —  the  first  flood  tide  for  Sept.  17.  Connect  these  dots  by  a  straight 
line.  Make  another  dot  for  2  :  46  P.M.  and  —10.3  feet,  —  the  second  ebb  tide  for  Sept.  17.  Draw  a  line 
from  this  dot  to  the  flood  tide  dot  preceding.  Continue  across  the  sheet  according  to  the  data  here  given : 


DAY, 
SEPT. 

HOUR 

IlKICHT, 

FEET 

DAT, 

SEPT. 

HOUR 

IlKICHT, 

FEET 

DAY. 
SEPT. 

HOUR 

Hr.ic.iiT, 
FKKT 

DAT, 

SEPT. 

HOUR 

IlKIiillT, 

FEET 

17. 

2:21  A.M. 

-10.3 

20., 

4  :  52  A.M. 

-11.8 

23. 

12:  66  A.M. 

10.4 

26. 

3:  30A.M. 

7.2 

8:28  A.M. 

9.8 

10:58  A.M. 

11.9 

7:12  A.M. 

-  10.2 

9:40  A.M. 

-7.1 

2:46  I-.M. 

-10.3 

5:17  P.M. 

-12.0 

1  :  16  P.M. 

10.8 

3:62  P.M. 

7.7 

8  :  62  P.M. 

10.8 

11:24  P.M. 

11.6 

7  :   13  P.M. 

-10.7 

10:35  I-.M. 

-7.7 

18. 

3:  ir>  A.M. 

-  11.0 

21. 

5:39  A.M. 

-  11.6 

24. 

1  :44  A.M. 

9.4 

27. 

1  :'J'.i    v.M. 

6.4 

9:21  A.M. 

10.8 

11  :45  A.M. 

10.9 

8:00  A.M. 

-    9.2 

10:60  A.M. 

-7.4 

3:40  P.M. 

-11.3 

6:05  P.M. 

-  12.1 

2:04  P.M. 

9.8 

4:63  P.M. 

7.0 

9:46  P.M. 

11.4 

8:33  P.M. 

-    8.6 

11  ::>.->  P.M. 

-7.1 

19. 

4:05  A.M. 

-11.5 

22. 

12:09  A.M. 

11.1 

25. 

2:  36  A.M. 

8.3 

28. 

6:31  A.M. 

6.9 

10:  10  A.M. 

11.5 

6  :  25  A.M. 

-11.1 

8:63  A.M. 

-    8.1 

11:52  A.M. 

-6.2 

4:29  P.M. 

-11.9 

12:30  P.M. 

11.5 

2  :  57  P.M. 

8.7 

5  :54  I'.M. 

6.6 

10:30  P.M. 

11.7 

6:53  P.M. 

-11.6 

9:28  P.M. 

-    8.6 

Make  a  small  circle  under  the  number  19  to  indicate  the  moon  was  full  Sept.  19;  and  under 
26  make  a  small  semicircle  convex  to  the  left  to  indicate  third  quarter  moon  Sept.  26. 
Questions.     1.   How  many  flood  tides  each  day?     How  many  ebb? 

2.  As  you  glance  over  the  graph,  do  the  tide  phenomena  of  one  day  appear  at  the  same  hour 
as  those  of  the  preceding  day,  or  are  they  earlier,  or  later  ?    Subtract  the  times  of  the  tides  Sept.  17 
from  the  times  of  the  corresponding  tides  Sept.  18,  and  the  times  of  the  tides  Sept.  18  from  the  times 
of  the  corresponding  tides  Sept.  19 ;   repeat  the  process  for  two  more  days.     What  is  the  average  differ- 
ence in  time  between  the  tides  of  one  day  and  the  corresponding  tides  of  the  next  day  ? 

3.  How  many  hours  and  minutes  on  the  average  from  one  flood  to  the  next  flood  ?   From  ebb 
to  ebb  ?     From  flood  to  ebb  ? 

4.  A  day  or  two  after  what  phase  of  the  moon  are  the  floods  uncommonly  high  ?    They  are  called 
"springtides."     When  are  the  floods  uncommonly  low  ?    They  are  called  "  neap  tides."      N.B.    Spring 
tides  occur  also  after  new  moon,  and  neap  tides  after  first  quarter. 

5.  How  does  the  neap  ebb  compare  with  the  spring  el>l>  ? 

6.  How  much  is  the  neap  tidal  range  (height  of  flood  above  ebb)?     How  much  is  the  spring 
range  ?    What  fraction  of  the  spring  range  is  the  neap  range  ?      N.B.  The  contrast  between  spring  and 
neap  here  shown  is  greater  than  the  average. 

Advanced  Questions.     7.    On  a  precipitous  coast  would  there  be  much,  or  little,  horizontal  movement 
of  water  in  the  rising  or  the  falling  tide  ? 

8.  How  would  the  tide  be  of  any  importance  in  the  use  of  shallow  harbors? 

9.  Why  do  vessels  sometimes  start  on  their  voyages  at  such  an  unseemly  hour  as  2  or  3  A.M.  ? 

174 


NEW  JERSEY.    ATLANTIC  CITY  SHEET 

Purpose.     To  study  the  sea  border  of  a  low  growing  plain. 

Description  of  the  Region.  The  part  of  New  Jersey  adjoining  the  region  represented  on  this 
map  is  a  sandy  plain,  generally  not  fertile,  and  covered  with  a  growth  of  inferior  pines.  The  alti- 
tude is  low,  the  relief  slight,  and  marshes  border  the  streams.  The  fertile  tracts  are  cultivated,  and 
considerable  fishing  is  done  along  the  coast,  but  the  seaside  resorts,  many  of  which  are  open  all 
the  year,  furnish  the  chief  occupation  of  the  people. 

Location  and  Extent.     1.   In  what  part  of  New  Jersey  is  this  region  ?     In  what  geographic  district  ? 

2.  How  many  miles  long  is  the  shore  of  the  mainland,  west  of  the  great  marsh,  in  the  northwest 
corner  of  the  map  ? 

Relief  and  Shore  Features.  3.  The  beaches,  which  make  the  actual  sea  border,  lie  how  far  from 
the  mainland  ? 

4.   What  lies  between  the  beaches  and  the  mainland  ? 

As  the  tide  comes  in,  the  creeks  are  filled  with  sea  water ;  as  the  tide  goes  out,  the  smaller  creeks 
are  completely  drained  and  the  larger  ones  partly  emptied. 

f>.    What  part  of  the  marsh  is  being  artificially  drained  (straight  blue  lines)  and  so  made  serviceable  V 

6.  From  what  names  do  you  infer  that  the  bays  and  connecting  waterways  are  navigable  to  small 
boats  and  yachts  ? 

7.  How  wide  are  Brigantiue  and  Island  beaches  ?    How  long  is  each  ? 

8.  What  is  their  highest  altitude?     Is  much  or  little  of  them  over  10  feet  above  sea  level? 

9.  How  does  the  north  end  of  Absecon  Beach  compare  with  the  other  beaches  in  width  and 
altitude?    Give  a  reason  for  the  location  of  Atlantic  City. 

10.  Do  the  ends  of  the  beaches  of  this  sheet  generally  "  hook  "  toward  the  mainland  or  toward 
the  ocean?    Give  a  reason. 

11.  How  many  lighthouses  are  there  on  this  sheet?    How  many  life-saving  stations?    Explain 
the  need  of  the  latter. 

12.  Which  border  of  the  beaches  is  the  smoother,  that  toward  the  sea  or  that  toward  the  marsh  ? 
Explain  why  it  is  so. 

13.  What  interrupts  the  straightness  of  the  line  in  which  the  mainland  meets  the  salt  marsh? 
What  sort  of  a  shore  would  a  perfectly  smooth  coastal  plain  have? 

Advanced  Questions.  14.  Make  a  sketch  map  of  one  of  the  tidal  creeks  and  its  tributaries  —  the 
small  streams  in  the  salt  marsh. 

15.  Does  the  mainland  within  ^  mile  of  the  salt  marsh  slope  more,  or  less,  than  at  a  distance  of 
one  or  two  miles  back?    Give  reason. 

16.  Where  did  the  sand  of  the  beaches  come  from  ?     What  agents  built  it  into  the  beaches? 

17.  Explain  the  formation  of  the  small  hills  on  the  beaches. 

18.  Why  are  there  so  many  seaside  resorts  on  the  New  Jersey  coast,  and  no  commercial  towns  ? 


176 


MAINE.     BOOTHBAY   SHEET 

Purpose.     To  study  the  ocean  border  of  a  high,  rocky  plain  well  dissected  by  rivers. 

Description  of  the  Region.  The  rocks  of  this  region  are  mainly  hard  and  crystalline.  The  glacial 
ice  swept  most  of  the  rock  waste  off  into  the  sea.  The  framework  of  the  hills  is  the  bed  rock,  but  the 
topography  is  considerably  modified  in  places  by  glacial  deposits.  The  depths  of  the  water  are  con- 
siderable,—  from  nearly  200  feet  in  Sheepscot  Bay  to  50  feet  in  Sheepscot  River  at  the  north  border  of 
the  map,  25  to  30  feet  in  Boothbay  Harbor.  This  is  sometimes  called  a  coast  of  small  fiords. 

Location  and  Extent.     1.    What  part  of  the  Maine  coast  is  here  represented? 

2.  How  many  miles  in  a  straight  line  is  Griffith  Head  from  Pemaquid  Point?  Following  the 
shore  line  it  is  about  100  miles. 

Relief  and  Shore  Features.     3.   Give  the  altitudes  of  four  or  five  large  hills. 

4.  The  ridges  and  valleys  extend  in  what  direction  ? 

5.  Give  the  height,  the  width,  and  the  length  of  four  of  the  named  islands  of  different  sizes.     In 
what  direction  do  they  extend  ?    Are  they  in  line  with  the  ridges  or  with  the  valleys  of  the  mainland  ? 
Explain  how  they  came  to  be  so. 

6.  Describe  the  size  and  altitude  of  the  ledges  at  43°  50'  N.      Why  do  you  suppose  they  are  not  of 
the  same  material  as  the  beaches  of  the  New  Jersey  coast  ? 

7.  Are  there  few  or  many  salt  marshes?    Where  are  they  located  ? 

8.  Give  as  many  evidences  as  you  can  that  the  land  was  once  higher  and  has  been  somewhat 
submerged. 

9.  Are  the  villages  located  near  the  shore,  or  inland ?     Why  there? 

10.  Notice  the  one  railroad  in  the  northwest  corner  of  the  map.     Why  does  it  not  run  down  to 
Boothbay  and  the  neighboring  villages  ? 

11.  What  means  of  transportation  have  the  people  of  these  villages? 

12.  Compare  the  number  of  lighthouses  and  life-saving  stations  here  with  that  on  the  New  Jersey 
sheet,  and  explain  the  difference. 

Advanced  Questions.  13.  Draw  a  cross  section  to  show  the  depth  of  water  from  the  south  end 
of  Damiscove  Island  west  to  the  mainland,  using  the  following  data  and  the  standard  vertical  scale. 


CM.  FROM  MAINLAND. 

0 

2 

4 

7 

8 

10 

12 

14 

15 

16 

FEET  DEEP. 

0 

60 

84 

192 

102 

136 

198 

150 

90 

0 

14.  Account  for  the  shallow  place  8  centimeters  from  the  west  end  of  the  section. 

15.  Draw  an  outline  map  of  Linekin  Neck  and  shade  the  part  that  would  be  submerged  if  the  land 
should  sink  100  feet. 


178 


OREGON.  PORT  ORFORD  SHEET 

Purpose.     To  study  a  narrow  coastal  plain  and  a  mountainous  coast. 

Description  of  the  Region.  This  sheet  represents  a  part  of  the  coast  mountains  in  southern  Oregon, 
and  part  of  a  narrow  coastal  plain  which  extends  from  the  village  of  Port  Orford  many  miles  north  of 
the  limits  of  this  sheet.  Although  most  of  the  rock  of  this  region  is  sedimentary,  volcanic  intrusions 
and  lava  flows  are  numerous.  Tower  Rock,  Castle  Rock,  Island  Rock,  and  some  otluT  islands  are 
probably  old  volcanic  necks.  This  whole  region  was  in  late  geologic  times  base-leveled  and  submerged, 
and  has  recently  been  elevated.  Nearly  everywhere  the  bed  rock  is  covered  by  only  a  thin  layer  of  rock 
waste,  but  on  the  coastal  plain  the  sand  and  gravel  varies  in  thickness  from  20  feet  at  the  base  of  the 
mountains  to  85  feet  at  the  sea  border. 

Topography  and  Coast  Features.  1.  What  is  the  width  of  the  plain  at  Cape  Blanco?  At  the 
northern  border  of  the  map?  What  is  its  altitude  at  Denmark? 

2.  Note  the  fine  brown  dotted  areas  that  represent  beach  sand.     Is  this  beach  sand  abundant  on 
the  rocky  points  ?  On  the  low  shores  ? 

3.  Why  does  not  Floras  Creek  flow  directly  west  into  the  ocean  as  it  once  did  V 

4.  How  was  Garrison  Lagoon,  near  Port  Orford  village,  formed?     Name  three  other  bodies  of 
water  on  this  sheet  that  were  similarly  formed. 


5.  Does  the  sheet  show  that  the  streams  of  this  region  have  steep,  or  gentle,  grades?  Therefore, 
do  they  carry  much  or  little  sediment?  What  evidently  becomes  of  the  sediment  brought  to  the  sea  by 
Elk  and  Sixes  rivers?  Therefore,  where  are  the  waves  building  up  the  shore  line? 


6.   How  does  the  coast  line  north  of  Point  Orford  compare  with  that  to  the  south  ?    Give  the 
reasons  for  the  differences. 


7.  Are  most  of  the  rocky  islets  located  off  rocky  promontories,  or  off  low  beaches  ?    Are  the  waves 
cutting,  or  building,  at  the  headlands  ? 

8.  Do  you  find  many  good  harbors  on  this  rising  coast  ?     If  the  land  should  sink  100  feet,  where 
would  there  be  good  harbors? 


180 


WINDS   AND  CURRENTS. 

Purpose.    To  study  the  relation  of  the  ocean  surface  circulation  to  the  planetary  winds. 


& 
OCEAN  CURRENTS" 


//>-7>i       I1-     V'lllIHHl.N    *tUMF.#   V>~         ii-     «-< 

^TH-' 


1.  Name  the  currents  in  the  trade  wind  belts  in  the  middle  of  the  oceans,  give  the  general  direc- 
tion in  which  they  move,  and  the  reason  for  this  movement. 

'2.  When  the  water  driven  by  the  trade  winds  reaches  the  western  side  of  the  oceans,  what  direc- 
tions does  it  take?  Give  the  names  applied  to  the  currents  formed  of  these  waters. 

3.  Name  the  currents  and  drifts  which  have  an  easterly  direction  in  latitudes  40°  to  60°,  and  give 
a  reason  for  their  direction. 

4.  Explain  what  becomes  of  the  water  of  each  of  these  drifts  when  it  reaches  the  eastern  side  of 
the  oceans,  and  give  the  names  of  the  currents  formed  of  it 

5.  What  is  the  direction  of  the  drift  in  the  Indian  Ocean  north  of  the  equator  in   winter  (large 
map)  ?    In  summer  (small  corner  map)  ?    Explain  the  difference. 

6.  Give  the  latitude  and  the  longitude  of  the  center  of  each  of  the  five  large  ocean  areas  that  have 
no  current.     Explain  why  there  are  no  currents  here. 

7.  Name  the  currents  or  drifts  that  exert  a  cooling  influence  on  the  shores  they  wash,  and  name 
the  countries  thus  affected  by  each. 

8.  Name  the  currents  or  drifts  that  exert  a  warming  influence,  and  the  countries  thus  affected  by 
each. 


182 


OCEAN  ROUTES 

Purpose.     To  learn  how  ocean  routes  are  influenced  by  prevailing  winds,  by  storms  and  currents. 
Material.     Pilot  charts  of  the  North  Pacific  and  North  Atlantic  <> <•  .-ans,  a  globe,  a  string. 

A.  The  North  Pacific  Ocean.      To  find  the  shortest  course  vessels  could  take  from  San  Francisco  to 
Yokohama,  Japan,  stretch  a  string  on  a  globe  between  these  two  places. 

1.  Is  it  an  east-west  line? 

On  the  North  Pacific  Pilot  Chart  this  is  called  the  Great  Circle  Route  between  San  Francisco  and 
Yokohama. 

2.  How  many  miles  long  is  it  ? 

3.  Reckoning  54J  miles  to  a  degree,  how  many  miles  are  there  from  San  Francisco  to  Yokohama 
in  an  east-west  line  ?    How  much  different  from  the  great  circle  route  ? 

4.  Give  a  reason  why  the  sailing  route  from  Yokohama  to   San  Francisco  is  so  different  from  the 
sailing  route  from  San  Francisco  to  China  and  Japan. 

5.  State  and  explain  the  difference  between  the  sailing  route  from  Juan  de  Fuca  to  San  Diego  and 
that  from  San  Diego  to  Juan  de  Fuca. 

6.  Describe  the  general  path  of  typhoons.     In  what  months  are  they  m<»t  frequent  '.'    (See  Table  of 
Storm  Tracks.) 

B.  The  North  Atlantic  Ocean.     7.    Explain  the  difference  between  the  sailing  route  from  the  English 
Channel  to  the  equator  and  that  from  the  equator  to  the  English  Channel. 

8.  Describe  the  route  from  New  York  to  the  equator,  and  explain  why  the  return  route  is  different. 

9.  Why  do  sailors  going  from  London  to  New  York  sometimes  go  as  far  south  as  latitude  '25°  N.  ? 
On  the  return  voyage  would  they  take  the  same  course? 

10.  Dense  fogs  are  common  on  the  Grand  Banks  southeast  of  Newfoundland  from  late  winter  till 
early  summer.     Icebergs  and  floes  (small  red  triangles  and  circles)  are  frequent  there  in  summer.     On 
account  of  these  dangers  how  do  the  spring  and  summer  steamer  routes  differ  from  the  fall  and  winter 
routes? 

11.  To  avoid  collisions  in  fog  or  storm  the  east-bound  steamer  routes  from  New  York  to  Europe  do 
not  coincide  with  the  west-bound  rout. •>.     Which  lies  further  north  ? 

12.  What  vessel  routes  lie  in  the  Gulf  Stream  going  northeast  but  avoid  the  Stream  going  in  tin- 
opposite  direction  ? 

13.  Heavy  red  lines  mark  the  storm  paths.     Routes  in  what  latitudes  are  most  subject  to  storms  7 

14.  If  you  find  any  hurricane  paths  mapped,  describe  the  path  and  give  the  months  in   which  the 
storms  occur. 

Advanced  Questions.     15.    Water  currents  and  drifts  are  marked  by  small  Mark   arrows.     Locate  the 
places  in  either  ocean  where  the  surface  water  movement  corresponds  with  the  prevailing  wind  direction. 

16.  What  kinds  of  vessels  seem  to  prefer  great  circle  routes?     What  kinds  adapt  their  routes  more 
to  the  prevailing  winds  ? 

17.  Of  the  hundreds  of  ships  plying  between  Europe  and  America,  why  does  a  voyager  meet  so 
few  ?    In  what  part  of  his  route  does  he  see  the  largest  number  ? 


184 


VEGETATION  REGION 


186 


RAINFALL   AND   VEGETATION 

Purpose.  To  study  the  distribution  of  rain  over  the  earth,  and  the  vegetation  areas  and  belts  de- 
pending on  rainfall  and  temperature. 

A.  Rainfall.  (Turn  to  your  study  of  the  Terrestrial  Wind  Belts,  p.  151,  and  review  the  latitudes,  and 
direction  of  winds,  of  each  belt.) 

1.  What  belt  around  the  earth  has  the  heaviest  rainfall ?     In  what  wind  belts  is  it? 

Are  there  any  dry  regions  in  it? 

2.  Between  what  latitude  boundaries  are  the  large  desert  areas  that  are  crossed  by  the  tropic  of 
Cancer  ?     By  the  tropic  of  Capricorn  ? 

On  which  side  of  the  land  masses  do  these  desert  areas  extend  down  to  the  ocean?  Explain  why 
this  is  so. 

3.  At  what  places  in  these  dry  belts  is  the  rainfall  heavy?     On  which  side  of  the  continents  an- 
these  places  ?    Give  a  reason  for  these  heavy  rainfalls. 


4.  In  what  wind  belt  are  the  dry  areas  of  Central  Asia  and  the  United  States?  Do  these  deserts 
extend  to  the  ocean  on  either  side  of  the  continent?  Give  a  reason.  Give  the  location  of  a  corresponding 
dry  region  in  the  southern  hemisphere. 


B.    Vegetation.     5.   Give  the  general  location  of  each  of  the  two  belts  which  include  most  of  the 
great  forest  regions  of  the  earth. 

The  forests  of  the  torrid  belt  are  very  different  from  those  of  the  cool  belt.     The  latter  are  mostly 
of  spruces,  firs,  and  pine's;  while  the  former  include  a  large  variety  of  broad-leaved  trees. 

6.  Carefully  compare  the  two  maps.     Are  the  forest  regions  generally  areas  of  heavy,  or  of  light 
rainfall?     Name  four  comparatively  small  regions  that  illustrate  your  answer. 

7.  Are   the  pasture  regions  areas   of  light  or  of  heavy  rainfall?     Name  several  regions  which 
illustrate  your  answer. 

8.  How  many  inches  of  rainfall  do  most  of  the  large  agricultural  regions  receive  ?     Why,  then,  in 
Egypt,  which  receives  a  desert  rainfall,  is  a  strip  marked  agricultural  ? 

9.  Does  the  northern  or  the  southern  hemisphere  have  the  large  tundra  regions?     Why? 

Advanced  Questions.     10.    In  which  hemisphere,  the  northern  or  the  southern,  do  the  areas  of  palms 
and  of  grain  extend  nearer  the  pole  ?     Give  reason. 

11.  Taking  20  inches  of  rainfall  as  the  dividing  line,  do  the  dry  areas,  or  the  moist,  occupy  tin- 
larger  portion  of  the  land  surface  ?    Name  a  continent  in  wliicli  the  opposite  condition  prevails. 

12.  Why  is  the  southern  part  of  South  America  rainy  on  the  west  side,  while  southwestern  Africa 
is  desert?  , 

13.  Are  the  long,  narrow  forest  regions  of  Europe  and  Asia  on  mountains  or  in  valleys?    Why? 

187 


PICTURE    SUPPLEMENT  —  RAINFALL   AND    VEGETATION 


Compare  these   two   pictures,  one  representing  a  cold-climate  forest,  the  other  representing  an 
equatorial  forest. 

1.  In  which  would  a  man  find  more  obstruction  by  bushes  and  vines? 

2.  In  which. are  the  trunks  set  more  closely  together? 

3.  How   has  this  crowding   and   consequent   loss  of   sunlight   affected   the    lower   branches   of 
the  spruce? 

4.  Which  forest  would  produce  the  straighter  timber  ? 

5.  In  what  two  ways  are  the  spruce  branches  adapted  to  shed  the  snow  ? 


189 


CONTENTS 

NUMBER  OF 
EXERCISE  NAME  OF  EXERCISE  I'A<;KS 


191 


Ni  Mi-,i:u  OK 
EXKKCISK  NAME  OF  EXERCISE  PACKS 


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4 


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